Silicon Laboratories Clock SI5316 User Manual

ANY-FREQUENCY PRECISION CLOCKS  
Si5316, Si5319, Si5322, Si5323, Si5324, Si5325,  
Si5326, Si5327, Si5365, Si5366, Si5367,  
Si5368, Si5369, Si5374, Si5375  
FAMILY REFERENCE MANUAL  
Rev. 0.5 6/11  
Copyright © 2011 by Silicon Laboratories  
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TABLE OF CONTENTS  
Section  
Page  
6.2.1. Input Clock Stability during Internal Self-Calibration  
6.2.2. Self-Calibration caused by Changes in Input Frequency  
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7. Microprocessor Controlled Parts (Si5319, Si5324, Si5325, Si5326,  
7.1.1. Jitter Tolerance (Si5319, Si5324, Si5325, Si5326, Si5327, Si5368,  
7.1.3. Narrowband Parts (Si5319, Si5324, Si5326, Si5327,  
7.2.4. Narrowband Input-to-Output Skew (Si5319, Si5324, Si5326, Si5327,  
7.4.1. Manual Clock Selection (Si5324, Si5325, Si5326, Si5367,  
7.4.2. Automatic Clock Selection (Si5324, Si5325, Si5326, Si5367,  
7.4.3. Hitless Switching with Phase Build-Out (Si5324, Si5326, Si5327,  
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7.9. Output Clock Drivers (Si5319, Si5324, Si5325, Si5326,  
7.10. PLL Bypass Mode (Si5319, Si5324, Si5325, Si5326, Si5327,  
7.11. Alarms (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367,  
7.11.1. Loss-of-Signal Alarms (Si5319, Si5324, Si5325, Si5326, Si5327,  
7.11.7. LOS Algorithm for Reference Clock Input (Si5319, Si5324, Si5326,  
2
7.13. I C Serial Microprocessor Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102  
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8.4. Crystal/Reference Clock Interfaces (Si5316, Si5319, Si5323,  
Appendix B—Frequency Plans and Jitter Performance (Si5316, Si5319,  
Si5374, Si5375) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121  
Appendix F—Typical Performance: Bypass Mode, PSRR, Crosstalk,  
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LIST OF FIGURES  
Figure 26. Narrowband PLL Divider Settings (Si5319, Si5324, Si5326,  
2
Figure 34. I C Command Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102  
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Figure 69. 27 MHz In; 148.35 MHz Out; Light Trace BW = 6 Hz;  
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LIST OF TABLES  
1
Table 3. Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
Table 5. DC Characteristics—Microprocessor Devices (Si5324, Si5325,  
Table 7. DC Characteristics—Narrowband Devices (Si5316, Si5319,  
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Table 52. Alarm Output Logic Equations  
1 2  
Table 58. Output Format Measurements , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109  
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1. Any-Frequency Precision Clock Product Family Overview  
Silicon Laboratories Any-Frequency Precision Clock products provide jitter attenuation and clock multiplication/  
clock division for applications requiring sub 1 ps rms jitter performance. The device product family is based on  
Silicon Laboratories' 3rd generation DSPLL technology, which provides any-frequency synthesis and jitter  
attenuation in a highly integrated PLL solution that eliminates the need for discrete VCXO/VCSOs and loop filter  
components. These devices are ideally suited for applications which require low jitter reference clocks, including  
OTN (OTU-1, OTU-2, OTU-3, OTU-4), OC-48/STM-16, OC-192/STM-64, OC-768/STM-256, GbE, 10GbE, Fibre  
Channel, 10GFC, synchronous Ethernet, wireless backhaul, wireless point-point infrastructure, broadcast video/  
HDTV (HD SDI, 3G SDI), test and measurement, data acquisition systems, and FPGA/ASIC reference clocking.  
Table 1 provides a product selector guide for the Silicon Laboratories Any-Frequency Precision Clocks. Three  
product families are available. The Si5316, Si5319, Si5323, Si5324, Si5326, Si5366, and Si5368 are jitter-  
attenuating clock multipliers that provide ultra-low jitter generation as low as 0.30 ps RMS. The devices vary  
according to the number of clock inputs, number of clock outputs, and control method. The Si5316 is a fixed-  
frequency, pin controlled jitter attenuator that can be used in clock smoothing applications. The Si5323 and Si5366  
are pin-controlled jitter-attenuating clock multipliers. The frequency plan for these pin-controlled devices is  
selectable from frequency lookup tables and includes common frequency translations for SONET/SDH, ITU G.709  
Forward Error Correction (FEC) applications (255/238, 255/237, 255/236, 238/255, 237/255, 236/255), Gigabit  
Ethernet, 10G Ethernet, 1G/2G/4G/8G/10G Fibre Channel, ATM and broadcast video (Genlock). The Si5319,  
Si5324, Si5326, Si5327, Si5368, and Si5369 are microprocessor-controlled devices that can be controlled via an  
2
I C or SPI interface. These microprocessor-controlled devices accept clock inputs ranging from 2 kHz to 710 MHz  
and generate multiple independent, synchronous clock outputs ranging from 2 kHz to 945 MHz and select  
frequencies to 1.4 GHz. Virtually any frequency translation combination across this operating range is supported.  
Independent dividers are available for every input clock and output clock, so the Si5324, Si5326, Si5327, and  
Si5368 can accept input clocks at different frequencies and generate output clocks at different frequencies. The  
Si5316, Si5319, Si5323, Si5326, Si5327, Si5366, Si5368, and Si5369 support a digitally programmable loop  
bandwidth that can range from 60 Hz to 8.4 kHz. An external (37–41 MHz, 55–61 MHz, 109–125.5 MHz, or 163–  
180 MHz) reference clock or a low-cost 114.285 MHz 3rd overtone crystal is required for these devices to enable  
ultra-low jitter generation and jitter attenuation. (See "Appendix A—Narrowband References" on page 119.) The  
Si5324 and Si5369 are much lower bandwidth devices, providing a user-programmable loop bandwidth from 4 to  
525 Hz.  
The Si5323, Si5324, Si5326, Si5327, Si5366, Si5368, and Si5369 support hitless switching between input clocks in  
compliance with GR-253-CORE and GR-1244-CORE that greatly minimizes the propagation of phase transients to  
the clock outputs during an input clock transition (<200 ps typ). Manual, automatic revertive and automatic non-  
revertive input clock switching options are available. The devices monitor the input clocks for loss-of-signal and  
provide a LOS alarm when missing pulses on any of the input clocks are detected. The devices monitor the lock  
status of the PLL and provide a LOL alarm when the PLL is unlocked. The lock detect algorithm works by  
continuously monitoring the phase of the selected input clock in relation to the phase of the feedback clock. The  
Si5326, Si5366, Si5368, and Si5369 monitor the frequency of the input clocks with respect to a reference  
frequency applied to an input clock or the XA/XB input, and generates a frequency offset alarm (FOS) if the  
threshold is exceeded. This FOS feature is available for SONET/SDH applications. Both Stratum 3/3E and SONET  
Minimum Clock (SMC) FOS thresholds are supported.  
The Si5319, Si5323, Si5324, Si5326, Si5366, Si5368, and Si5369 provide a digital hold capability that allows the  
device to continue generation of a stable output clock when the selected input reference is lost. During digital hold,  
the DSPLL generates an output frequency based on a historical average that existed a fixed amount of time before  
the error event occurred, eliminating the effects of phase and frequency transients that may occur immediately  
preceding entry into digital hold.  
The Si5322, Si5325, Si5365, and Si5367 are frequency flexible, low jitter clock multipliers that provide jitter  
generation of 0.6 ps RMS without jitter attenuation. These devices provide low jitter integer clock multiplication or  
fractional clock synthesis, but they are not as frequency-flexible as the Si5319/23/24/26/66/68/69. The devices  
vary according to the number of clock inputs, number of clock outputs, and control method. The Si5322 and Si5365  
are pin-controlled clock multipliers. The frequency plan for these devices is selectable from frequency lookup  
tables.  
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A wide range of settings are available, but they are a subset of the frequency plans supported by the Si5323 and  
Si5366 jitter-attenuating clock multipliers. The Si5325 and Si5367 are microprocessor-controlled clock multipliers  
2
that can be controlled via an I C or SPI interface.  
These devices accept clock inputs ranging from 10 MHz to 710 MHz and generate multiple independent,  
synchronous clock outputs ranging from 10 MHz to 945 MHz and select frequencies to 1.4 GHz. The Si5325 and  
Si5367 support a subset of the frequency translations available in the Si5319, Si5324, Si5326, Si5327, Si5368, and  
Si5369 jitter-attenuating clock multipliers. The Si5325 and Si5367 can accept input clocks at different frequencies  
and generate output clocks at different frequencies. The Si5322, Si5325, Si5365, and Si5367 support a digitally  
programmable loop bandwidth that ranges from 150 kHz to 1.3 MHz. No external components are required for  
these devices. LOS and FOS monitoring is available for these devices, as described above.  
The Si5374 and Si5375 are quad DSPLL versions of the Si5324 and Si5319, respectively. Each of the four  
DSPLLs can operate at completely independent frequencies. The only resources that they share are a common  
2
I C bus and a common XA/XB jitter reference oscillator. The Si5375 consists of four one-input and one-output  
DSPLLs. The Si5374 consists of four two-input and two-output DSPLLs with very low loop bandwidth.  
The Any-Frequency Precision Clocks have differential clock output(s) with programmable signal formats to support  
LVPECL, LVDS, CML, and CMOS loads. If the CMOS signal format is selected, each differential output buffer  
generates two in-phase CMOS clocks at the same frequency. For system-level debugging, a PLL bypass mode  
drives the clock output directly from the selected input clock, bypassing the internal PLL.  
Silicon Laboratories offers a PC-based software utility, DSPLLsim, that can be used to determine valid frequency  
plans and loop bandwidth settings for the Any-Frequency Precision Clock product family. For the microprocessor-  
controlled devices, DSPLLsim provides the optimum PLL divider settings for a given input frequency/clock  
multiplication ratio combination that minimizes phase noise and power consumption. Two DSPLLsim configuration  
software applications are available for the 1-PLL and 4-PLL devices, respectively. DSPLLsim can also be used to  
Other useful documentation, including device data sheets and programming files for the microprocessor-controlled  
devices are available from this website.  
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Table 1. Product Selection Guide  
Part  
Control Number of  
Input  
Output  
RMS Phase Jitter  
PLL  
Hitless  
Free  
Package  
Number  
Inputsand Frequency Frequency (12 kHz–20 MHz) Bandwidth Switching Run  
*
*
Outputs  
Mode  
(MHz)  
(MHz)  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
Si5315  
Si5316  
Si5317  
Si5319  
Si5323  
Si5324  
Si5326  
Si5327  
Si5366  
Si5368  
Si5369  
Si5374  
Si5375  
Pin  
Pin  
Pin  
1PLL, 2 | 2 0.008–644 0.008–644  
0.45 ps  
0.3 ps  
0.3 ps  
0.3 ps  
0.3 ps  
0.3 ps  
0.3 ps  
0.5 ps  
0.3 ps  
0.3 ps  
0.3 ps  
0.4 ps  
0.4 ps  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
1PLL, 2 | 1  
1PLL, 1 | 2  
19–710  
1–710  
19–710  
1–710  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
2
I C/SPI 1PLL, 1 | 1 0.002–710 0.002–1417  
Pin 1PLL, 2 | 2 0.008–707 0.008–1050  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
4 Hz to  
525 Hz  
6x6 mm  
36-QFN  
2
I C/SPI 1PLL, 2 | 2 0.002–710 0.002–1417  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
2
I C/SPI 1PLL, 2 | 2 0.002–710 0.002–1417  
60 Hz to  
8 kHz  
6x6 mm  
36-QFN  
2
I C/SPI 1PLL, 2 | 2 0.002–710 0.002–808  
60 Hz to  
8 kHz  
14x14 mm  
100-TQFP  
Pin  
1PLL, 4 | 5 0.008–707 0.008–1050  
60 Hz to  
8 kHz  
14x14 mm  
100-TQFP  
2
I C/SPI 1PLL, 4 | 5 0.002–710 0.002–1417  
4 Hz to  
525 Hz  
14x14 mm  
100-TQFP  
2
I C/SPI 1PLL, 4 | 5 0.002–710 0.002–1417  
4 Hz to  
525 Hz  
10x10 mm  
80-BGA  
2
I C  
4PLL, 8 | 8 0.002–710 0.002–808  
4PLL, 4 | 4 0.002–710 0.002–808  
60 Hz to  
8 kHz  
10x10 mm  
80-BGA  
2
I C  
*Note: Maximum input and output rates may be limited by speed rating of device. See each device’s data sheet for ordering  
information.  
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Table 2. Product Selection Guide (Si5322/25/65/67)  
Low Jitter Precision Clock Multipliers (Wideband)  
Si5322  
Si5325  
Si5365  
Si5367  
2
2
4
4
2
2
5
5
707  
710  
707  
710  
1050  
1400  
1050  
1400  
0.6 ps rms typ  
0.6 ps rms typ  
0.6 ps rms typ  
0.6 ps rms typ  
Notes:  
1. Maximum input and output rates may be limited by speed rating of device. See each device’s data sheet for ordering  
information.  
2. Requires external low-cost, fixed frequency 3rd overtone 114.285 MHz crystal or reference clock. See "Table 60.XA/XB  
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2. Narrowband vs. Wideband Overview  
The narrowband (NB) devices offer a number of features and capabilities that are not available with the wideband  
(WB) devices, as outlined in the below list:  
Broader set of frequency plans due to more divisor options  
Hitless switching between input clocks  
Lower minimum input clock frequency  
Lower loop bandwidth  
Digital Hold (reference-based holdover instead of VCO freeze)  
FRAMESYNC realignment  
CLAT and FLAT (input to output skew adjust)  
INC and DEC pins  
PLL Loss of Lock status indicator  
FOS is not supported.  
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3. Any-Frequency Clock Family Members  
3.1. Si5316  
The Si5316 is a low jitter, precision jitter attenuator for high-speed communication systems, including OC-48, OC-  
192, 10G Ethernet, and 10G Fibre Channel. The Si5316 accepts dual clock inputs in the 19, 38, 77, 155, 311, or  
622 MHz frequency range and generates a jitter-attenuated clock output at the same frequency. Within each of  
these clock ranges, the device can be tuned approximately 14% higher than nominal SONET/SDH frequencies, up  
to a maximum of 710 MHz in the 622 MHz range. The DSPLL loop bandwidth is digitally selectable, providing jitter  
performance optimization at the application level. Operating from a single 1.8, 2.5, or 3.3 V supply, the Si5316 is  
ideal for providing jitter attenuation in high performance timing applications. See "6. Pin Control Parts (Si5316,  
Si5322, Si5323, Si5365, Si5366)" on page 50 for a complete description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
CK1DIV  
SFOUT[1:0]  
f3_1  
2
2
CKIN_1+  
CKIN_1–  
÷ N31  
÷ N32  
0
1
0
1
fOSC  
2
CKOUT+  
CKOUT–  
DSPLL®  
f3  
f3_2  
CKIN_2+  
CKIN_2–  
DBL_BY  
CK2DIV  
C1B  
Signal  
Detect  
C2B  
RST  
CS  
Bandwidth  
Control  
BWSEL[1:0]  
FRQSEL[1:0]  
Control  
Frequency  
Control  
LOL  
VDD  
GND  
Figure 1. Si5316 Any-Frequency Jitter Attenuator Block Diagram  
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3.2. Si5319  
The Si5319 is a jitter-attenuating precision M/N clock multiplier for applications requiring sub 1 ps jitter  
performance. The Si5319 accepts one clock input ranging from 2 kHz to 710 MHz and generates one clock output  
ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The Si5319 can also use its crystal oscillator as  
a clock source for frequency synthesis. The device provides virtually any frequency translation combination across  
this operating range. The Si5319 input clock frequency and clock multiplication ratio are programmable through an  
®
I2C or SPI interface. The Si5319 is based on Silicon Laboratories' 3rd-generation DSPLL technology, which  
provides any-frequency synthesis and jitter attenuation in a highly integrated PLL solution that eliminates the need  
for external VCXO and loop filter components. The DSPLL loop bandwidth is digitally programmable, providing  
jitter performance optimization at the application level. Operating from a single 1.8, 2.5, or 3.3 V supply, the Si5319  
is ideal for providing clock multiplication and jitter attenuation in high performance timing applications. See "7.  
Si5375)" on page 76 for a complete description.  
Xtal or Refclock  
XO  
÷ N32  
®
DSPLL  
CKOUT  
f3  
÷ N1_HS  
÷ NC1  
÷ N31  
CKIN  
÷ N2  
VDD  
GND  
Loss of Signal  
Loss of Lock  
Control  
Signal Detect  
I2C/SPI Port  
Xtal/Clock Select  
Device Interrupt  
Rate Select  
Figure 2. Si5319 Any-Frequency Jitter Attenuating Clock Multiplier Block Diagram  
18  
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3.3. Si5322  
The Si5322 is a low jitter, precision clock multiplier for applications requiring clock multiplication without jitter  
attenuation. The Si5322 accepts dual clock inputs ranging from 19.44 to 707 MHz and generates two frequency-  
multiplied clock outputs ranging from 19.44 to 1050 MHz. The input clock frequency and clock multiplication ratio  
are selectable from a table of popular SONET, Ethernet, Fibre Channel, and broadcast video (HD SDI, 3G SDI)  
rates. The DSPLL loop bandwidth is digitally selectable from 150 kHz to 1.3 MHz. Operating from a single 1.8, 2.5,  
or 3.3 V supply, the Si5322 is ideal for providing low jitter clock multiplication in high performance timing  
description.  
0
2
CKOUT_1+  
CKOUT_2–  
2
CKIN_1+  
CKIN_1–  
0
1
fOSC  
f3  
DSPLL®  
2
SFOUT[1:0]  
1
CKIN_2+  
CKIN_2–  
0
1
2
CKOUT_2+  
CKOUT_2–  
C1B  
Signal  
Detect  
DBL2_BY  
C2B  
AUTOSEL  
Bandwidth  
Control  
CS_CA  
BWSEL[1:0]  
FRQTBL  
Control  
Frequency  
Control  
FRQSEL[3:0]  
RST  
VDD  
GND  
Figure 3. Si5322 Low Jitter Clock Multiplier Block Diagram  
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3.4. Si5323  
The Si5323 is a jitter-attenuating precision clock multiplier for high-speed communication systems, including  
SONET OC-48/OC-192, Ethernet, Fibre Channel, and broadcast video (HD SDI, 3G SDI). The Si5323 accepts  
dual clock inputs ranging from 8 kHz to 707 MHz and generates two frequency-multiplied clock outputs ranging  
from 8 kHz to 1050 MHz. The input clock frequency and clock multiplication ratio are selectable from a table of  
popular SONET, Ethernet, Fibre Channel, and broadcast video rates. The DSPLL loop bandwidth is digitally  
selectable, providing jitter performance optimization at the application level. Operating from a single 1.8, 2.5, or  
3.3 V supply, the Si5323 is ideal for providing clock multiplication and jitter attenuation in high-performance timing  
description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
0
1
2
CKOUT_1+  
CKOUT_1–  
2
2
CKIN_1+  
CKIN_1–  
0
1
f3  
fOSC  
DSPLL®  
SFOUT[1:0]  
CKIN_2+  
CKIN_2–  
0
1
2
CKOUT_2+  
CKOUT_2–  
C1B  
Signal  
Detect  
DBL2/BY  
C2B  
AUTOSEL  
LOL  
Bandwidth  
Control  
CS/CA  
BWSEL[1:0]  
FRQTBL  
FRQSEL[3:0]  
INC  
Control  
Frequency  
Control  
VDD  
GND  
DEC  
RST  
Figure 4. Si5323 Jitter Attenuating Clock Multiplier Block Diagram  
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3.5. Si5324  
The Si5324 is a jitter-attenuating precision clock multiplier for applications requiring sub 1 ps jitter performance.  
The Si5324 accepts dual clock inputs ranging from 2 kHz to 710 MHz and generates two independent,  
synchronous clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The device provides  
virtually any frequency translation combination across this operating range. The Si5324 input clock frequency and  
2
clock multiplication ratios are programmable through an I C or SPI interface. The DSPLL loop bandwidth is digitally  
programmable, providing jitter performance optimization at the application level. The Si5324 features loop  
bandwidth values as low as 4 Hz. Operating from a single 1.8, 2.5, or 3.3 V supply, the Si5324 is ideal for providing  
clock multiplication and jitter attenuation in high-performance timing applications. See "7. Microprocessor  
for a complete description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
3
0
1
DSPLL  
BYPASS  
2
2
CKIN_1 +  
CKIN_1 –  
÷ N31  
÷ N32  
0
1
f3  
CKIN_2 +  
CKIN_2 –  
DSPLL®  
1
0
fOSC  
2
2
CKOUT_1 +  
CKOUT_1 –  
/
÷ NC1  
÷ N1_HS  
÷ NC2  
INT_C1B  
C2B  
Signal  
Detect  
1
0
/
CKOUT_2 +  
CKOUT_2 –  
÷ N2  
LOL  
CS_CA  
CMODE  
SDA_SDO  
SCL  
SDI  
Control  
A[2]/SS  
A[1:0]  
INC  
DEC  
RST  
VDD  
GND  
Figure 5. Si5324 Clock Multiplier and Jitter Attenuator Block Diagram  
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3.6. Si5325  
The Si5325 is a low jitter, precision clock multiplier for applications requiring clock multiplication without jitter  
attenuation. The Si5325 accepts dual clock inputs ranging from 10 to 710 MHz and generates two independent,  
synchronous clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The Si5325 input  
2
clock frequency and clock multiplication ratios are programmable through an I C or SPI interface. The DSPLL loop  
bandwidth is digitally programmable from 150 kHz to 1.3 MHz. Operating from a single 1.8, 2.5, or 3.3 V supply, the  
Si5325 is ideal for providing clock multiplication in high performance timing applications. See "7. Microprocessor  
for a complete description.  
0
1
BYPASS  
2
CKIN_1 +  
÷ N31  
0
f3  
CKIN_1 –  
2
fOSC  
1
0
CKIN_2 +  
CKIN_2 –  
1
2
CKOUT_1 +  
CKOUT_1 –  
DSPLL®  
÷ N2  
÷ N32  
÷ NC1  
÷ N1_HS  
÷ NC2  
/
INT_C1B  
C2B  
Signal  
Detect  
1
0
2
/
CKOUT_2 +  
CKOUT_2 –  
CMODE  
SDA_SDO  
SCL  
Control  
SDI  
A[2]/SS  
A[1:0]  
RST  
VDD  
GND  
Figure 6. Si5325 Low Jitter Clock Multiplier Block Diagram  
22  
Rev. 0.5  
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3.7. Si5326  
The Si5326 is a jitter-attenuating precision clock multiplier for applications requiring sub 1 ps jitter performance.  
The Si5326 accepts dual clock inputs ranging from 2 kHz to 710 MHz and generates two independent,  
synchronous clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The device provides  
virtually any frequency translation combination across this operating range. The Si5326 input clock frequency and  
2
clock multiplication ratios are programmable through an I C or SPI interface. The DSPLL loop bandwidth is digitally  
programmable from 60 Hz to 8 kHz, providing jitter performance optimization at the application level. Operating  
from a single 1.8, 2.5, or 3.3 V supply, the Si5326 is ideal for providing clock multiplication and jitter attenuation in  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
3
0
1
DSPLL  
BYPASS  
2
2
CKIN_1 +  
CKIN_1 –  
÷ N31  
÷ N32  
0
1
f3  
CKIN_2 +  
CKIN_2 –  
DSPLL®  
1
0
fOSC  
2
2
CKOUT_1 +  
CKOUT_1 –  
÷ NC1  
÷ N1_HS  
÷ NC2  
/
INT_C1B  
C2B  
Signal  
Detect  
1
0
/
CKOUT_2 +  
CKOUT_2 –  
÷ N2  
LOL  
CS_CA  
CMODE  
SDA_SDO  
SCL  
SDI  
Control  
A[2]/SS  
A[1:0]  
INC  
DEC  
RST  
VDD  
GND  
Figure 7. Si5326 Clock Multiplier and Jitter Attenuator Block Diagram  
Rev. 0.5  
23  
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Si53xx-RM  
3.8. Si5327  
The Si5327 is a jitter-attenuating precision clock multiplier for applications requiring sub 1 ps jitter performance.  
The Si5327 accepts dual clock inputs ranging from 2 kHz to 710 MHz and generates two independent,  
synchronous clock outputs ranging from 2 kHz to 808 MHz. The device provides virtually any frequency translation  
combination across this operating range. The Si5327 input clock frequency and clock multiplication ratios are  
2
programmable through an I C or SPI interface. The DSPLL loop bandwidth is digitally programmable, providing  
jitter performance optimization at the application level. The Si5327 features loop bandwidth values as low as 4 Hz.  
Operating from a single 1.8, 2.5, or 3.3 V supply, the Si5327 is ideal for providing clock multiplication and jitter  
attenuation in high-performance timing applications. See "7. Microprocessor Controlled Parts (Si5319, Si5324,  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
3
0
1
DSPLL  
BYPASS  
2
2
CKIN_1 +  
CKIN_1 –  
÷ N31  
÷ N32  
0
1
f3  
CKIN_2 +  
CKIN_2 –  
DSPLL®  
1
0
fOSC  
2
CKOUT_1 +  
CKOUT_1 –  
÷ NC1  
÷ N1_HS  
÷ NC2  
/
INT_C1B  
C2B  
Signal  
Detect  
1
0
2
/
CKOUT_2 +  
CKOUT_2 –  
÷ N2  
LOL  
CS_CA  
CMODE  
SDA_SDO  
SCL  
SDI  
Control  
A[2]/SS  
A[1:0]  
INC  
DEC  
RST  
VDD  
GND  
Figure 8. Si5327 Clock Multiplier and Jitter Attenuator Block Diagram  
24  
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3.9. Si5365  
The Si5365 is a low jitter, precision clock multiplier for applications requiring clock multiplication without jitter  
attenuation. The Si5365 accepts four clock inputs ranging from 19.44 MHz to 707 MHz and generates five  
frequency-multiplied clock outputs ranging from 19.44 MHz to 1050 MHz. The input clock frequency and clock  
multiplication ratio are selectable from a table of popular SONET, Ethernet, Fibre Channel, and broadcast video  
rates. The DSPLL loop bandwidth is digitally selectable. Operating from a single 1.8, 2.5 V, or 3.3 V supply, the  
Si5365 is ideal for providing clock multiplication in high performance timing applications. See "6. Pin Control Parts  
BYPASS/  
DSBL2  
2
2
2
2
CKIN_1+  
CKIN_1–  
÷ N3_1  
÷ N3_2  
÷ N3_3  
÷ N3_4  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
÷ NC1  
÷ NC2  
÷ NC3  
CKIN_2+  
CKIN_2–  
f3  
1
0
fOSC  
CKOUT_2+  
CKOUT_2–  
÷ N1_HS  
DSPLL®  
CKIN_3+  
CKIN_3–  
DBL2_BY  
1
0
CKOUT_3+  
CKOUT_3–  
CKIN_4+  
CKIN_4–  
÷ N2  
DBL34  
DIV34[1:0]  
1
0
CKOUT_4+  
CKOUT_4–  
2
2
÷ NC4  
÷ NC5  
C1B  
C2B  
C3B  
1
0
CKOUT_5+  
CKOUT_5–  
ALRMOUT  
C1A  
Control  
DBL5  
C2A  
CS0_C3A  
CS1_C4A  
VDD  
GND  
Figure 9. Si5365 Low Jitter Clock Multiplier Block Diagram  
Rev. 0.5  
25  
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3.10. Si5366  
The Si5366 is a jitter-attenuating precision clock multiplier for high-speed communication systems, including  
SONET OC-48/OC-192, Ethernet, and Fibre Channel. The Si5366 accepts four clock inputs ranging from 8 kHz to  
707 MHz and generates five frequency-multiplied clock outputs ranging from 8 kHz to 1050 MHz. The input clock  
frequency and clock multiplication ratio are selectable from a table of popular SONET, Ethernet, Fibre Channel,  
and broadcast video (HD SDI, 3G SDI) rates. The DSPLL loop bandwidth is digitally selectable from 60 Hz to  
8 kHz, providing jitter performance optimization at the application level. Operating from a single 1.8, 2.5, or 3.3 V  
supply, the Si5366 is ideal for providing clock multiplication and jitter attenuation in high performance timing  
description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
BYPASS/DSBL2  
3
2
2
2
2
CKIN_1+  
CKIN_1–  
÷ N3_1  
÷ N3_2  
÷ N3_3  
÷ N3_4  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
fx  
÷ NC1  
÷ NC2  
÷ NC3  
CKIN_2+  
CKIN_2–  
f3  
DSPLL®  
1
0
fOSC  
CKOUT_2+  
CKOUT_2–  
÷ N1_HS  
CKIN_3+  
CKIN_3–  
DBL2_BY  
1
0
CKOUT_3+  
CKOUT_3–  
CKIN_4+  
CKIN_4–  
÷ N2  
DBL34  
CKOUT_2  
CKIN_3  
DIV34[1:0]  
FSYNC  
LOGIC/  
ALIGN  
1
0
CKOUT_4+  
CKOUT_4–  
2
2
CK_CONF  
C1B  
÷ NC4  
÷ NC5  
CKIN_4  
C2B  
C3B  
ALRMOUT  
C1A  
FSYNC  
1
0
CKOUT_5+  
CKOUT_5–  
Control  
DBL5  
C2A  
CS0_C3A  
CS1_C4A  
LOL  
VDD  
GND  
Figure 10. Si5366 Jitter Attenuating Clock Multiplier Block Diagram  
26  
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3.11. Si5367  
The Si5367 is a low jitter, precision clock multiplier for applications requiring clock multiplication without jitter  
attenuation. The Si5367 accepts four clock inputs ranging from 10 to 707 MHz and generates five frequency-  
multiplied clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The Si5367 input clock  
2
frequency and clock multiplication ratio are programmable through an I C or SPI interface. The DSPLL loop  
bandwidth is digitally programmable from 150 kHz to 1.3 MHz. Operating from a single 1.8, 2.5, or 3.3 V supply, the  
Si5367 is ideal for providing clock multiplication in high performance timing applications. See "7. Microprocessor  
for a complete description.  
BYPASS/DSBL2  
3
CKIN_1+  
CKIN_1–  
2
2
2
2
÷ N3_1  
÷ N3_2  
÷ N3_3  
÷ N3_4  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
2
2
÷ NC1  
÷ NC2  
÷ NC3  
÷ NC4  
÷ NC5  
CKIN_2+  
CKIN_2–  
f3  
1
0
DSPLL®  
fOSC  
CKOUT_2+  
CKOUT_2–  
CKIN_3+  
CKIN_3–  
÷ N1_HS  
DSBL2/BYPASS  
CKIN_4+  
CKIN_4–  
1
0
CKOUT_3+  
CKOUT_3–  
÷ N2  
DSBL34  
1
0
CKOUT_4+  
CKOUT_4–  
C1B  
C2B  
C3B  
1
0
CKOUT_5+  
CKOUT_5–  
DSBL5  
INT_ALM  
C1A  
Control  
C2A  
CS0_C3A  
CS1_C4A  
VDD  
GND  
Figure 11. Si5367 Clock Multiplier Block Diagram  
Rev. 0.5  
27  
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3.12. Si5368  
The Si5368 is a jitter-attenuating precision clock multiplier for applications requiring sub 1 ps rms jitter  
performance. The Si5368 accepts four clock inputs ranging from 2 kHz to 710 MHz and generates five  
independent, synchronous clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The  
device provides virtually any frequency translation combination across this operating range. The Si5368 input clock  
2
frequency and clock multiplication ratio are programmable through an I C or SPI interface. The DSPLL loop  
bandwidth is digitally programmable from 60 Hz to 8 kHz, providing jitter performance optimization at the  
application level. Operating from a single 1.8, 2.5, or 3.3 V supply, the Si5368 is ideal for providing clock  
multiplication and jitter attenuation in high performance timing applications. See "7. Microprocessor Controlled  
complete description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
BYPASS/DSBL2  
3
CKIN_1+  
CKIN_1–  
2
2
2
2
÷ N3_1  
÷ N3_2  
÷ N3_3  
÷ N3_4  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
2
2
fx  
÷ NC1  
÷ NC2  
÷ NC3  
÷ NC4  
÷ NC5  
CKIN_2+  
CKIN_2–  
f3  
DSPLL®  
1
0
fOSC  
CKOUT_2+  
CKOUT_2–  
CKIN_3+  
CKIN_3–  
÷ N1_HS  
DSBL2/BYPASS  
CKIN_4+  
CKIN_4–  
1
0
CKOUT_3+  
CKOUT_3–  
÷ N2  
DSBL34  
CKOUT_2  
CKIN_3  
1
0
CKOUT_4+  
CKOUT_4–  
FSYNC  
LOGIC/  
ALIGN  
CKIN_4  
C1B  
C2B  
C3B  
1
0
CKOUT_5+  
CKOUT_5–  
FSYNC  
DSBL5  
INT_ALM  
C1A  
Control  
C2A  
CS0_C3A  
CS1_C4A  
LOL  
VDD  
GND  
Figure 12. Si5368 Clock Multiplier and Jitter Attenuator Block Diagram  
28  
Rev. 0.5  
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3.13. Si5369  
The Si5369 is a jitter-attenuating precision clock multiplier for applications requiring sub 1 ps rms jitter  
performance. The Si5369 accepts four clock inputs ranging from 2 kHz to 710 MHz and generates five  
independent, synchronous clock outputs ranging from 2 kHz to 945 MHz and select frequencies to 1.4 GHz. The  
device provides virtually any frequency translation combination across this operating range. The Si5369 input clock  
2
frequency and clock multiplication ratio are programmable through an I C or SPI interface. The DSPLL loop  
bandwidth is digitally programmable, providing loop bandwidth values as low as 4 Hz. Operating from a single 1.8,  
2.5, or 3.3 V supply, the Si5369 is ideal for providing clock multiplication and jitter attenuation in high performance  
Si5368, Si5369, Si5374, Si5375)" on page 76 for a complete description.  
Xtal or Refclock  
RATE[1:0]  
XB  
XA  
BYPASS/DSBL2  
3
2
2
2
2
CKIN_1+  
CKIN_1–  
÷ N3_1  
÷ N3_2  
÷ N3_3  
÷ N3_4  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
2
2
fx  
÷ NC1  
÷ NC2  
÷ NC3  
÷ NC4  
÷ NC5  
CKIN_2+  
CKIN_2–  
f3  
DSPLL®  
1
0
fOSC  
CKOUT_2+  
CKOUT_2–  
÷ N1_HS  
CKIN_3+  
CKIN_3–  
DSBL2/BYPASS  
CKIN_4+  
CKIN_4–  
1
0
CKOUT_3+  
CKOUT_3–  
÷ N2  
DSBL34  
CKOUT_2  
CKIN_3  
1
0
CKOUT_4+  
CKOUT_4–  
FSYNC  
LOGIC/  
ALIGN  
CKIN_4  
C1B  
C2B  
C3B  
1
0
CKOUT_5+  
CKOUT_5–  
FSYNC  
DSBL5  
INT_ALM  
C1A  
Control  
C2A  
CS0_C3A  
CS1_C4A  
LOL  
VDD  
GND  
Figure 13. Si5369 Clock Multiplier and Jitter Attenuator Block Diagram  
3.14. Si5374/75 Compared to Si5324/19  
In general, the Si5374 can be viewed as a quad version of the Si5324 and the Si5375 can be viewed as a quad  
version of the Si5319. However, there are not exactly the same. This is an overview of the differences:  
1. The Si5374/75 cannot use a crystal as its OSC reference. It requires the use of a single external single-ended  
or differential crystal oscillator.  
2
2
2. The Si5374/75 only supports I C as its serial port protocol and does not have SPI. No I C address pins are  
available on the Si5374/75.  
3. The Si5374/75 does not provide separate INT_CK1B and CK2B pins to indicate when CKIN1 and CKIN2 do not  
have valid clock inputs. Instead, the IRQ pin can be programmed to function as one pin, the other pin or both.  
4. Selection of the OSC frequency is done by a register (RATE_REG), not by using the RATE pins.  
5. The Si5374/75 uses a different version of DSPLLsim: Si537xDSPLLsim.  
6. The Si5374/75 does not support 3.3 V operation.  
Rev. 0.5  
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3.15. Si5374  
The Si5374 is a highly integrated, 4-PLL jitter-attenuating precision clock multiplier for applications requiring sub 1  
ps jitter performance. Each of the DSPLL® clock multiplier engines accepts two input clocks ranging from 2 kHz to  
710 MHz and generates two independent, synchronous output clocks ranging from 2 kHz to 808 MHz. Each  
DSPLL provides virtually any frequency translation across this operating range. For asynchronous, free-running  
clock generation applications, the Si5374’s reference oscillator can be used as a clock source for the four DSPLLs.  
The Si5374 input clock frequency and clock multiplication ratio are programmable through an I2C interface. The  
Si5374 is based on Silicon Laboratories' 3rd-generation DSPLL® technology, which provides any-frequency  
synthesis and jitter attenuation in a highly integrated PLL solution that eliminates the need for external VCXO and  
loop filter components. Each DSPLL loop bandwidth is digitally programmable from 4 to 525 Hz, providing jitter  
performance optimization at the application level. The device operates from a single 1.8 or 2.5 V supply with on-  
chip voltage regulators with excellent PSRR. The Si5374 is ideal for providing clock multiplication and jitter  
attenuation in high port count optical line cards requiring independent timing domains.  
PLL Bypass  
Input Stage  
Synthesis Stage  
Output Stage  
CKIN1P_A  
CKIN1N_A  
PLL Bypass  
CKOUT1P_A  
CKOUT1N_A  
÷ N31  
Input  
Monitor  
÷ NC1  
f3  
f3  
f3  
®
fOSC  
DSPLL  
÷ NC1_HS  
÷ NC1_HS  
÷ NC1_HS  
÷ NC1_HS  
CKIN2P_A  
CKIN2N_A  
Hitless  
Switch  
A
÷ NC2  
÷ N32  
CKOUT2P_A  
CKOUT2N_A  
Internal  
Osc  
PLL Bypass  
÷ N2  
PLL Bypass  
CKIN3P_B  
CKIN3N_B  
PLL Bypass  
CKOUT3P_B  
CKOUT3N_B  
÷ N31  
÷ N32  
Input  
Monitor  
÷ NC1  
®
®
®
fOSC  
fOSC  
fOSC  
DSPLL  
CKIN4P_B  
CKIN4N_B  
Hitless  
Switch  
B
÷ NC2  
CKOUT4P_B  
CKOUT4N_B  
Internal  
Osc  
PLL Bypass  
÷ N2  
PLL Bypass  
CKIN5P_C  
CKIN5N_C  
PLL Bypass  
CKOUT5P_C  
CKOUT5N_C  
÷ N31  
÷ N32  
Input  
Monitor  
÷ NC1  
DSPLL  
CKIN6P_C  
CKIN6N_C  
Hitless  
Switch  
C
÷ NC2  
CKOUT6P_C  
CKOUT6N_C  
Internal  
Osc  
PLL Bypass  
÷ N2  
PLL Bypass  
CKIN7P_D  
CKIN7N_D  
PLL Bypass  
CKOUT7P_D  
CKOUT7N_D  
÷ N31  
÷ N32  
Input  
Monitor  
÷ NC1  
f3  
DSPLL  
CKIN8P_D  
CKIN8N_D  
Hitless  
Switch  
D
÷ NC2  
CKOUT8P_D  
CKOUT8N_D  
Internal  
Osc  
PLL Bypass  
÷ N2  
RSTL_q  
CS_q  
VDD_q  
GND  
High PSRR  
Voltage Regulator  
Status / Control  
OSC_P/N  
Low Jitter  
XO or Clock  
SCL SDA  
IRQ_q  
LOL_q  
Figure 14. Si5374 Functional Block Diagram  
30  
Rev. 0.5  
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3.16. Si5375  
The Si5375 is a highly integrated, 4-PLL jitter-attenuating precision clock multiplier for applications requiring sub 1  
ps jitter performance. Each of the DSPLL® clock multiplier engines accepts an input clock ranging from 2 kHz to  
710 MHz and generates an output clock ranging from 2 kHz to 808 MHz. Each DSPLL provides virtually any  
frequency translation combination across this operating range. For asynchronous, free-running clock generation  
applications, the Si5375’s reference oscillator can be used as a clock source for any of the four DSPLLs. The  
Si5375 input clock frequency and clock multiplication ratio are programmable through an I2C interface. The Si5375  
is based on Silicon Laboratories' third-generation DSPLL® technology, which provides any-frequency synthesis  
and jitter attenuation in a highly integrated PLL solution that eliminates the need for external VCXO and loop filter  
components. Each DSPLL loop bandwidth is digitally programmable from 60 Hz to 8 kHz, providing jitter  
performance optimization at the application level. The device operates from a single 1.8 or 2.5 V supply with on-  
chip voltage regulators with excellent PSRR. The Si5375 is ideal for providing clock multiplication and jitter  
attenuation in high port count optical line cards requiring independent timing domains.  
PLL Bypass  
Input Stage  
Synthesis Stage  
Output Stage  
CKIN1P_A  
CKIN1N_A  
÷ N31  
Input  
Monitor  
PLL Bypass  
CKOUT1P_A  
CKOUT1N_A  
f3  
fOSC  
®
DSPLL  
÷ NC1_HS  
÷ NC1_HS  
÷ NC1_HS  
÷ NC1  
A
÷ N32  
÷ N2  
PLL Bypass  
CKIN1P_B  
CKIN1N_B  
÷ N31  
÷ N32  
Input  
Monitor  
PLL Bypass  
CKOUT1P_B  
CKOUT1N_B  
f3  
fOSC  
®
®
®
DSPLL  
÷ NC1  
B
÷ N2  
PLL Bypass  
CKIN1P_C  
CKIN1N_C  
÷ N31  
÷ N32  
Input  
Monitor  
PLL Bypass  
CKOUT1P_C  
CKOUT1N_C  
fOSC  
f3  
DSPLL  
÷ NC1  
C
÷ N2  
PLL Bypass  
CKIN1P_D  
CKIN1N_D  
÷ N31  
÷ N32  
Input  
Monitor  
PLL Bypass  
CKOUT1P_D  
CKOUT1N_D  
fOSC  
f3  
DSPLL  
÷ NC1_HS  
÷ NC1  
D
÷ N2  
RSTL_q  
CS_q  
VDD_q  
GND  
High PSRR  
Voltage Regulator  
Status / Control  
OSC_P/N  
Low Jitter  
SCL SDA  
IRQ_q  
LOL_q  
XO or Clock  
Figure 15. Si5375 Functional Block Diagram  
Rev. 0.5  
31  
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Si53xx-RM  
4. Device Specifications  
The following tables are intended to simplify device selection. The specifications in the individual device data  
sheets take precedence over this document. Refer to the respective device data sheet for devices not listed in the  
tables below.  
Table 3. Recommended Operating Conditions1  
Parameter  
Symbol Test Condition  
Min Typ Max Unit  
Ambient  
Temperature  
T
–40 25  
85  
ºC  
A
Supply Voltage  
During Normal  
Operation  
V
3.3 V Nominal  
2.5 V Nominal  
1.8 V Nominal  
2.97 3.3 3.63  
2.25 2.5 2.75  
1.71 1.8 1.89  
V
V
V
DD  
Note:  
1. All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions.  
Typical values apply at nominal supply voltages and an operating temperature of 25 ºC unless otherwise stated.  
2. See Sections 6.7.1 and 8.2.1 for restrictions on output formats for TQFP devices at 3.3 V.  
V
SIGNAL +  
Single-Ended  
Peak-to-Peak Voltage  
Differential I/Os  
V
ICM , V  
VISE,VOSE  
SIGNAL – OCM  
(SIGNAL +) – (SIGNAL –)  
ICM, VOCM  
Differential Peak-to-Peak Voltage  
V ,VOD  
ID  
V
t
SIGNAL +  
SIGNAL –  
VID = (SIGNAL+) – (SIGNAL–)  
Figure 16. Differential Voltage Characteristics  
80%  
20%  
CKIN, CKOUT  
tF  
tR  
Figure 17. Rise/Fall Time Characteristics  
32  
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Table 4. DC Characteristics  
Parameter  
Symbol  
Test Condition  
Min Typ Max Units  
Supply Current  
(Independent of  
Supply Voltage)  
I
LVPECL Format  
622.08 MHz Out  
All CKOUT’s  
Enabled  
251 279  
394 435  
mA  
mA  
DD  
LVPECL Format  
622.08 MHz Out  
Only 1 CKOUT  
Enabled  
217 243  
253 284  
mA  
mA  
CMOS Format  
19.44 MHz Out  
All CKOUTs  
Enabled  
204 234  
278 321  
mA  
mA  
CMOS Format  
19.44 MHz Out  
Only 1 CKOUT  
Enabled  
194 220  
229 261  
mA  
mA  
Disable Mode  
165  
mA  
V
CKIN_n Input Pins  
Input Common  
Mode Voltage  
(Input Threshold  
Voltage)  
V
1.8 V ± 10%  
2.5 V ± 10%  
3.3 V ± 10%  
Single-ended  
0.9  
1.0  
1.1  
20  
40  
1.4  
1.7  
1.95  
60  
ICM  
Input Resistance  
CKN  
k  
RIN  
Single-Ended Input  
Voltage Swing  
V
f
f
f
f
< 212.5 MHz  
0.2  
V
ISE  
CKIN  
PP  
> 212.5 MHz  
0.25  
0.2  
V
CKIN  
PP  
Differential Input  
Voltage Swing  
V
< 212.5 MHz  
V
ID  
CKIN  
PP  
> 212.5 MHz  
0.25  
V
CKIN  
PP  
Notes:  
1. Refer to Section 6.7.1 and 8.2.1 for restrictions on output formats for TQFP devices at 3.3 V.  
2. This is the amount of leakage that the 3L inputs can tolerate from an external driver. See Figure 55 on page 115.  
3. No under- or overshoot is allowed.  
Rev. 0.5  
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Table 4. DC Characteristics (Continued)  
Parameter  
Symbol  
Test Condition  
Min Typ Max Units  
Output Clocks  
(CKOUTn—See “8.2. Output Clock Drivers” for Configuring Output Drivers for LVPECL/CML/LVDS/CMOS)  
Common Mode  
V
LVPECL 100   
load line-to-line  
V
1.42  
V
DD  
1.25  
V
OCM  
DD  
Differential Output  
Swing  
V
LVPECL 100   
1.1  
1.9  
V
OD  
PP  
PP  
load line-to-line  
Single Ended  
Output Swing  
V
LVPECL 100   
0.5  
0.93  
V
SE  
load line-to-line  
Differential Output  
Voltage  
CKO  
CKO  
CML 100 load  
350 425 500 mV  
PP  
VD  
line-to-line  
Common Mode  
Output Voltage  
CML 100 load  
V
V
VCM  
DD  
line-to-line  
– .36  
Differential  
Output Voltage  
CKO  
LVDS 100 load  
500 700 900 mV  
VD  
PP  
PP  
line-to-line  
Low swing LVDS  
100 load  
350 425 500 mV  
line-to-line  
Common Mode  
Output Voltage  
CKO  
LVDS 100 load  
1.125 1.2 1.275  
170 200 230  
V
VCM  
line-to-line  
Differential Output  
Resistance  
CKO  
CML, LVPECL,  
LVDS, Disabled,  
Sleep  
RD  
Output Voltage Low  
Output Voltage High  
Notes:  
CKO-  
VOLLH  
CKO-  
VOHLH  
CMOS  
0.4  
V
V
V
= 1.71 V  
0.8 x  
DD  
V
CMOS  
DD  
1. Refer to Section 6.7.1 and 8.2.1 for restrictions on output formats for TQFP devices at 3.3 V.  
2. This is the amount of leakage that the 3L inputs can tolerate from an external driver. See Figure 55 on page 115.  
3. No under- or overshoot is allowed.  
34  
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Table 4. DC Characteristics (Continued)  
Parameter  
Symbol  
Test Condition  
Min Typ Max Units  
Output Drive  
CKO  
CMOS  
IO  
Current (CMOS driv-  
Driving into CKO-  
ing into CKO  
for  
for output low  
VOL  
VOL  
output low or CKO-  
or CKO  
for out-  
VOH  
for output high.  
put high. CKOUT+  
and CKOUT–  
shorted externally.  
VOH  
CKOUT+ and  
CKOUT- shorted  
externally)  
V
= 1.8 V  
DD  
ICMOS[1:0] = 11  
ICMOS[1:0] = 10  
ICMOS[1:0] = 01  
ICMOS[1:0] = 00  
7.5  
5.5  
mA  
mA  
mA  
mA  
3.5  
1.75  
V
= 3.3 V  
32  
32  
mA  
mA  
DD  
ICMOS[1:0] = 11  
ICMOS[1:0] = 10  
ICMOS[1:0] = 01  
ICMOS[1:0] = 00  
24  
16  
8
mA  
mA  
mA  
2-Level LVCMOS Input Pins  
Input Voltage Low  
V
V
V
V
V
V
V
= 1.71 V  
= 2.25 V  
= 2.97 V  
= 1.89 V  
= 2.25 V  
= 3.63 V  
0.5  
0.7  
0.8  
V
V
V
V
V
V
IL  
DD  
DD  
DD  
DD  
DD  
DD  
Input Voltage High  
V
1.4  
1.8  
2.5  
IH  
3-Level Input Pins  
Input Voltage Low  
V
0.15 x  
V
V
ILL  
V
DD  
Input Voltage Mid  
Input Voltage High  
V
0.45 x  
0.55 x  
IMM  
V
V
DD  
DD  
V
I
0.85 x  
V
IHH  
V
DD  
Input Low Current  
See note  
–20  
µA  
ILL  
Notes:  
1. Refer to Section 6.7.1 and 8.2.1 for restrictions on output formats for TQFP devices at 3.3 V.  
2. This is the amount of leakage that the 3L inputs can tolerate from an external driver. See Figure 55 on page 115.  
3. No under- or overshoot is allowed.  
Rev. 0.5  
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Table 4. DC Characteristics (Continued)  
Parameter  
Symbol  
Test Condition  
Min Typ Max Units  
Input Mid Current  
Input High Current  
I
See note  
–2  
2
µA  
µA  
IMM  
I
See note  
20  
IHH  
LVCMOS Output Pins  
Output Voltage Low  
V
I = 2 mA  
0.4  
0.4  
V
V
OL  
O
V
V
= 1.62 V  
DD  
I = 2 mA  
O
= 2.97 V  
DD  
Output Voltage High  
V
I = –2 mA  
V
V
V
OH  
O
DD –  
0.4  
V
= 1.62 V  
DD  
I = –2 mA  
V
O
DD –  
0.4  
V
= 2.97 V  
DD  
Tri-State Leakage  
Current  
I
RST = 0  
–100  
100  
µA  
OZ  
Notes:  
1. Refer to Section 6.7.1 and 8.2.1 for restrictions on output formats for TQFP devices at 3.3 V.  
2. This is the amount of leakage that the 3L inputs can tolerate from an external driver. See Figure 55 on page 115.  
3. No under- or overshoot is allowed.  
36  
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Table 5. DC Characteristics—Microprocessor Devices (Si5324, Si5325, Si5367, Si5368)  
Parameter  
Symbol  
Test Condition  
Min  
Typ  
Max  
Units  
2
I C Bus Lines (SDA, SCL)  
Input Voltage Low  
Input Voltage High  
Input Current  
V
0.7 x V  
–10  
0.25 x V  
V
V
ILI2C  
DD  
V
V
DD  
IHI2C  
DD  
DD  
I
VIN = 0.1 x V  
10  
µA  
II2C  
DD  
to 0.9 x V  
DD  
Hysteresis of Schmitt trig-  
ger inputs  
V
V
= 1.8 V  
DD  
0.1 x V  
V
V
V
HYSI2C  
V
V
= 2.5 or 3.3 V  
0.05 x V  
DD  
DD  
Output Voltage Low  
V
V
= 1.8 V  
0.2 x V  
DD  
OHI2C  
DD  
IO = 3 mA  
= 2.5 or 3.3 V  
IO = 3 mA  
0.4  
V
DD  
Table 6. SPI Specifications (Si5324, Si5325, Si5367, and Si5368)  
Parameter  
Symbol  
Test Conditions  
Min  
Typ  
Max  
60  
Unit  
%
Duty Cycle, SCLK  
t
SCLK = 10 MHz  
40  
100  
DC  
Cycle Time, SCLK  
t
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
c
Rise Time, SCLK  
t
20–80%  
20–80%  
20–20%  
80–80%  
25  
25  
r
Fall Time, SCLK  
t
f
Low Time, SCLK  
t
30  
30  
lsc  
High Time, SCLK  
t
hsc  
Delay Time, SCLK Fall to SDO Active  
Delay Time, SCLK Fall to SDO Transition  
Delay Time, SS Rise to SDO Tri-state  
Setup Time, SS to SCLK Fall  
Hold Time, SS to SCLK Rise  
Setup Time, SDI to SCLK Rise  
Hold Time, SDI to SCLK Rise  
Delay Time between Slave Selects  
t
25  
25  
25  
d1  
d2  
d3  
t
t
t
25  
20  
25  
20  
25  
su1  
t
h1  
t
su2  
t
h2  
t
cs  
Note: All timing is referenced to the 50% level of the waveform unless otherwise noted. Input test levels are VIH = V – 4 V,  
DD  
VIL = 0.4 V.  
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tc  
tr  
t
f
SCLK  
thsc  
tlsc  
tsu1  
th1  
SS  
tcs  
tsu2  
th2  
SDI  
td1  
td3  
td2  
SDO  
Figure 18. SPI Timing Diagram  
Table 7. DC Characteristics—Narrowband Devices (Si5316, Si5319, Si5323, Si5366, Si5368)  
Parameter  
Symbol  
Test Condition  
Min  
Typ  
Max  
Unit  
Single-Ended Reference Clock Input Pin XA (XB with cap to gnd)  
Input Resistance  
XA  
XA  
(RATE[1:0] = LM, ML, MH, or HM)  
0
10  
k  
RIN  
Input Voltage Level Limits  
Input Voltage Swing  
1.2  
1.2  
V
VIN  
XA  
0.5  
V
PP  
VPP  
Differential Reference Clock Input Pins (XA/XB)  
Differential Input Voltage  
Level Limits  
XA/XB  
(RATE[1:0] = LM, ML, MH, or HM)  
0
1.2  
2.4  
V
VIN  
Input Voltage Swing  
XA  
/XB  
0.5  
V
PP  
VPP  
VPP  
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CLKOUT_2  
CLKIN_4*  
1/fFSYNC  
tFSSU  
tFSH  
FSYNC_ALIGN  
FSYNCOUT*  
tLATF  
Fixed number of CLKOUT_2  
clock cycles.  
* CLKIN_2 and CLKIN_4 are the active input clock and frame sync pair in this example  
Figure 19. Frame Synchronization Timing  
Rev. 0.5  
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Table 8. AC Characteristics—All Devices  
Symbol  
Test Condition  
Min  
Typ  
Max  
Units  
Parameter  
Input Frequency  
19.38  
19.43  
0.002  
10  
710  
MHz  
707.35 MHz  
707.35 MHz  
CKN  
F
710  
MHz  
MHz  
kHz  
0.008  
When used as frame  
synchronization input  
2
512  
CKIN_n Input Pins  
Input Duty Cycle  
(Minimum Pulse  
Width)  
Whichever is smaller  
(i.e., the 40% / 60 %  
limitation applies only  
to high frequency  
clocks)  
40  
2
60  
%
         
         
ns  
CKN  
DC  
Input Capacitance CKN  
3
pF  
ns  
         
         
CIN  
Input Rise/Fall  
Time  
CKN  
20–80%  
11  
TRF  
CKOUT_n Output Pins (See individual data sheets for speed grade limits)  
Output Frequency  
(Output not  
configured for  
CMOS or tri-state)  
19.38  
19.43  
0.008  
10  
710  
1049  
1049  
945  
MHz  
MHz  
MHz  
MHz  
MHz  
MHz  
GHz  
MHz  
CK  
OF  
0.002  
970  
945  
1134  
1.4  
   
   
   
   
1.213  
Maximum Output CKO  
Frequency in  
CMOS Format  
212.5  
         
         
         
FMC  
TRF  
Output Rise/Fall  
(20–80%) at  
622.08 MHz  
CKO  
Output not config-  
ured for CMOS See  
230  
350  
8
ps  
ns  
CMOS Output  
Output Rise/Fall  
(20–80%) at  
212.5 MHz  
V
= 1.62  
DD  
Cload = 5 pF  
CKO  
TRF  
CMOS Output  
2
ns  
ps  
     
V
= 2.97  
DD  
Cload = 5 pF  
Output Duty Cycle CKO  
Differential  
100 Load  
Line to Line  
±40  
         
DC  
Uncertainty  
Measured at 50%  
Point (not for CMOS)  
40  
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Table 8. AC Characteristics—All Devices (Continued)  
Symbol  
Test Condition  
Min  
Typ  
Max  
Units  
Parameter  
LVCMOS Pins  
Input Capacitance  
C
1
3
pF  
µs  
         
         
in  
Minimum Reset  
Pulse Width  
t
RSTMN  
Reset to Micropro-  
cessor Access  
Ready  
t
10  
ms  
   
   
READY  
LVCMOS Output Pins  
LOSn Trigger  
Window  
From last CKIN_n  
to internal detection  
of LOSn  
100 x  
N3  
570 x  
N3  
T
   
CKIN  
From last CKIN_n   
to internal detection  
of LOSn  
0.8 x  
N3  
4.5 x N3 T  
CKIN  
LOS  
TRIG  
N3 1  
From last CKIN_n   
to internal detection  
of LOSn  
250 ns  
4.5  
T
CKIN  
N3 = 1  
Time to Clear LOL  
after LOS Cleared  
t
LOS to LOL  
Assume  
10  
ms  
CLRLOL  
Fold = Fnew,  
Stable XA/XB  
reference  
Rev. 0.5  
41  
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Table 8. AC Characteristics—All Devices (Continued)  
Symbol  
Test Condition  
Min  
Typ  
Max  
Units  
Parameter  
Device Skew  
Output Clock  
Skew,  
t
of CKOUT_n to of  
CKOUT_m,  
100  
ps  
        
SKEW  
see Section 7.7.4  
CKOUT_n and  
CKOUT_m at same  
frequency and signal  
format  
PHASE OFFSET = 0  
SQICAL = 1  
CKOUT_ALWAYS_O  
N = 1  
Coarse Skew  
Adjust Resolution  
t
Using CLAT[7:0]  
1/F  
ps  
ps  
PHRES  
VCO  
VCO  
register  
using INC/DEC pins  
1/F  
Coarse Skew  
Adjust Range  
t
Using CLAT[7:0]  
  
+  
PHSRNG  
register  
using INC/DEC pins  
  
9
+  
s
Fine Skew Adjust  
Resolution  
t
using FLAT[14:0]  
ps  
FPHSRES  
register  
Fine Skew Adjust  
Range  
t
using FLAT[14:0]  
–110  
110  
ps  
FPHSRNG  
register  
Phase Offset  
Resolution  
t
using PHASEOFF-  
SETn[7:0] registers  
N1_HS/  
OFSTRES  
f
VCO  
Phase Offset  
Range  
t
using PHASEOFF-  
SETn[7:0] registers  
–128 x  
127 x  
OFSTRNG  
t
t
OF-  
OF-  
STRES  
STRES  
PLL Performance  
Lock Time  
t
1.2  
sec  
ms  
RST with valid  
CKIN to LOL;  
BW = 100 Hz  
LOCKHW  
Pin Reset or  
t
10  
   
   
READY  
Register Reset to  
Microprocessor  
Access Ready  
Reset to first on  
CKOUT  
t
Valid, stable clock on  
CKIN  
1
35  
1.2  
sec  
µs  
   
   
START  
Minimum Reset  
Pulse Width  
t
         
RSTMIN  
Lock Time  
t
Start of ICAL to of  
LOL,  
1000  
ms  
LOCKMP  
lowest BW setting  
Closed Loop Jitter  
Peaking  
0.05  
0.1  
dB  
         
J
PK  
42  
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Si53xx-RM  
Table 8. AC Characteristics—All Devices (Continued)  
Symbol  
Test Condition  
Min  
Typ  
Max  
Units  
Parameter  
Output Phase  
Change due to  
Temperature Vari-  
ation  
Max phase changes  
from –40 to +85 °C  
300  
500  
ps  
         
t
TEMP  
Jitter Tolerance  
         
J
TOL  
Phase Noise  
fout = 622.08 MHz  
1 kHz Offset  
–106  
–87 dBc/Hz  
CKO  
PN  
10 kHz Offset  
100 kHz Offset  
1 MHz Offset  
–121  
–132  
–132  
–88  
–100 dBc/Hz  
–110 dBc/Hz  
–125 dBc/Hz  
Subharmonic  
Noise  
Phase Noise @  
100 kHz Offset  
–76  
dBc  
SP  
SP  
SUBH  
SPUR  
Spurious Noise  
–93  
–70  
dBc  
Rev. 0.5  
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Table 9. Jitter Generation (Si5316, Si5324, Si5366, Si5368)  
1,2,3,4,5  
Parameter  
Symbol  
Min  
Typ  
Max  
GR-253 Spec  
Unit  
Test Condition  
Measurement  
Filter (MHz)  
DSPLL  
2
Bandwidth  
0.02–80  
120 Hz  
120 Hz  
120 Hz  
4.2  
.27  
3.7  
.14  
4.4  
.26  
6.2  
.42  
6.4  
.31  
6.9  
.41  
30 ps pp/0.3 UIpp  
N/A  
ps  
PP  
ps  
rms  
4–80  
10 ps pp/0.1 UIpp  
N/A  
ps  
PP  
J
Jitter Gen OC-192  
GEN  
ps  
rms  
0.05–80  
10 ps pp/0.1 UIpp  
ps  
PP  
1.0 ps  
ps  
rms  
rms  
(0.01 UI  
rms  
0.012–20  
120 Hz  
3.5  
.27  
5.4  
.41  
40.2 ps pp/  
(0.1 UIpp)  
ps  
PP  
J
Jitter Gen OC-48  
GEN  
4.02 ps  
ps  
rms  
rms  
(0.01 UI  
rms  
Notes:  
1. Test condition: f = f  
= 622.08 MHz, LVPECL clock input: 1.19 Vppd with 0.5 ns rise/fall time (20–80%), LVPECL  
OUT  
IN  
clock output.  
2. BWSEL [1:0] loop bandwidth settings provided in Pin Descriptions.  
3. 114.285 MHz 3rd OT crystal used as XA/XB input.  
4. V = 2.5 V  
DD  
5. T = 85 °C  
A
Table 10. Jitter Generation (Si5322, Si5325, Si5365, Si5367)  
1,2  
Symbol  
Min  
Typ  
Max  
Unit  
Parameter  
Test Condition  
Measurement  
Filter (MHz)  
DSPLL  
2
Bandwidth  
(kHz)  
Jitter Gen OC-192  
J
0.02–80  
4–80  
1096  
1096  
1096  
1096  
.49  
.23  
.47  
.48  
ps  
ps  
ps  
ps  
GEN  
rms  
rms  
rms  
rms  
0.05–80  
0.012–20  
Jitter Gen OC-48  
J
GEN  
Notes:  
1. Test condition: f = f  
= 622.08 MHz, LVPECL clock input: 1.19 Vppd with 0.5 ns rise/fall time (20–80%), LVPECL  
IN  
OUT  
clock output.  
2. BWSEL [1:0] loop bandwidth settings provided in Pin Descriptions.  
44  
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Table 11. Thermal Characteristics  
Parameter  
Symbol Test Condition  
Devices  
Value  
Unit  
Thermal Resistance Junction to Ambient  
Still Air  
Si5316, Si5319,  
Si5322, Si5323,  
Si5324, Si5325  
32  
ºC/W  
JA  
Si5365, Si5366,  
Si5367, Si5368  
40  
14  
ºC/W  
ºC/W  
Thermal Resistance Junction to Case  
Still Air  
Si5316, Si5319,  
Si5322, Si5323,  
Si5324, Si5325  
JC  
Rev. 0.5  
45  
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5. DSPLL (All Devices)  
All members of the Any-Frequency Precision Clocks family incorporate a phase-locked loop (PLL) that utilizes  
Silicon Laboratories' third generation DSPLL technology to eliminate jitter, noise, and the need for external VCXO  
and loop filter components found in discrete PLL implementations. This is achieved by using a digital signal  
processing (DSP) algorithm to replace the loop filter commonly found in discrete PLL designs. Because external  
PLL components are not required, sensitivity to board-level noise sources is minimized. This digital technology  
provides highly stable and consistent operation over process, temperature, and voltage variations.  
A simplified block diagram of the DSPLL is shown in Figure 20. This algorithm processes the phase detector error  
term and generates a digital frequency control word M to adjust the frequency of the digitally-controlled oscillator  
(DCO). The narrowband configuration devices (Si5316, Si5319, Si5323, Si5324, Si5326, Si5327, Si5366, Si5368,  
and Si5369) provide ultra-low jitter generation by using an external jitter reference clock and jitter attenuation. For  
applications where basic frequency multiplication of low jitter clocks is all that is required, the wideband parts  
(Si5322, Si5325, Si5365, and Si5367) are available.  
DSPLL  
M
Fvco  
Digital Loop  
Filter  
fIN  
Phase  
Detector  
Digital  
DCO  
fOUT  
Figure 20. Any-Frequency Precision Clock DSPLL Block Diagram  
46  
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5.1. Clock Multiplication  
Fundamental to these parts is a clock multiplication circuit that is simplified in Figure 21. By having a large range of  
dividers and multipliers, nearly any output frequency can be created from a fixed input frequency. For typical  
telecommunications and data communications applications, the hardware control parts (Si5316, Si5322, Si5323,  
Si5365, and Si5366) provide simple pin control.  
The microprocessor controlled parts (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5368, and Si5369)  
provide a programmable range of clock multiplications. To assist users in finding valid divider settings for a  
particular input frequency and clock multiplication ratio, Silicon Laboratories offers PC-based software (DSPLLsim)  
that calculates these settings automatically. When multiple divider combinations produce the same output  
frequency, the software recommends the divider settings yielding the recommended settings for phase noise  
performance and power consumption.  
DSPLL  
f3  
Fin  
Divide By N3  
Phase  
Detector  
fVCO  
Digital Loop  
Filter  
Digital  
DCO  
Divide By NC1  
Fout  
Divide By N2  
fOUT = (Fin/N3) x N2/NC1  
fvco = (Fin/N3) x N2  
Figure 21. Clock Multiplication Circuit  
Rev. 0.5  
47  
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5.2. PLL Performance  
All members of the Any-Frequency Precision Clock family of devices provide extremely low jitter generation, a well-  
controlled jitter transfer function, and high jitter tolerance. For more information the loop bandwidth and its effect on  
5.2.1. Jitter Generation  
Jitter generation is defined as the amount of jitter produced at the output of the device with a jitter free input clock.  
Generated jitter arises from sources within the VCO and other PLL components. Jitter generation is a function of  
the PLL bandwidth setting. Higher loop bandwidth settings may result in lower jitter generation, but may result in  
less attenuation of jitter that might be present on the input clock signal.  
5.2.2. Jitter Transfer  
Jitter transfer is defined as the ratio of output signal jitter to input signal jitter for a specified jitter frequency. The  
jitter transfer characteristic determines the amount of input clock jitter that passes to the outputs. The DSPLL  
technology used in the Any-Frequency Precision Clock devices provides tightly controlled jitter transfer curves  
because the PLL gain parameters are determined largely by digital circuits which do not vary over supply voltage,  
process, and temperature. In a system application, a well-controlled transfer curve minimizes the output clock jitter  
variation from board to board and provides more consistent system level jitter performance.  
The jitter transfer characteristic is a function of the loop bandwidth setting. Lower bandwidth settings result in more  
jitter attenuation of the incoming clock, but may result in higher jitter generation. Section 1 Any-Frequency  
Precision Clock Product Family Overview also includes specifications related to jitter bandwidth and peaking.  
Figure 22 shows the jitter transfer curve mask.  
Jitter  
Transfer  
Jitter Out  
20 x LOG  
(
)
Jitter In  
0 dB  
Peaking  
–20 dB/dec.  
fJitter  
BW  
Figure 22. PLL Jitter Transfer Mask/Template  
48  
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5.2.3. Jitter Tolerance  
Jitter tolerance is defined as the maximum peak-to-peak sinusoidal jitter that can be present on the incoming clock  
before the DSPLL loses lock. The tolerance is a function of the jitter frequency, because tolerance improves for  
lower input jitter frequency.  
The jitter tolerance of the DSPLL is a function of the loop bandwidth setting. Figure 23 shows the general shape of  
the jitter tolerance curve versus input jitter frequency. For jitter frequencies above the loop bandwidth, the tolerance  
is a constant value A . Beginning at the PLL bandwidth, the tolerance increases at a rate of 20 dB/decade for  
j0  
lower input jitter frequencies.  
Input  
Jitter  
–20 dB/dec.  
Amplitude  
Excessive Input Jitter Range  
Aj0  
BW  
BW/100 BW/10  
fJitter In  
Figure 23. Jitter Tolerance Mask/Template  
The equation for the high frequency jitter tolerance can be expressed as a function of the PLL loop bandwidth (i.e.,  
bandwidth):  
5000  
BW  
------------  
ns pk-pk  
Aj0  
=
For example, the jitter tolerance when f = 155.52 MHz, f = 622.08 MHz and the loop bandwidth (BW) is 100 Hz:  
in  
out  
5000  
100  
------------  
Aj0  
=
= 50 ns pk-pk  
Rev. 0.5  
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6. Pin Control Parts (Si5316, Si5322, Si5323, Si5365, Si5366)  
These parts provide high-performance clock multiplication with simple pin control. Many of the control inputs are  
three levels: High, Low, and Medium. High and Low are standard voltage levels determined by the supply voltage:  
V
and Ground. If the input pin is left floating, it is driven to nominally half of V . Effectively, this creates three  
DD  
DD  
logic levels for these controls.  
These parts span a range of applications and I/O capacity as shown in Table 12.  
Table 12. Si5316, Si5322, Si5323, Si5365 and Si5366 Key Features  
Si5316  
Si5322  
Si5323  
Si5365  
Si5366  
SONET Frequencies  
DATACOM Frequencies  
DATACOM/SONET internetworking  
Fixed Ratio between input clocks  
Flexible Frequency Plan  
2
2
2
2
4
5
4
5
Number of Inputs  
Number of Outputs  
Jitter Attenuation  
2
1
6.1. Clock Multiplication (Si5316, Si5322, Si5323, Si5365, Si5366)  
By setting the tri-level FRQSEL[3:0] pins these devices provide a wide range of standard SONET and data  
communications frequency scaling, including simple integer frequency multiplication to fractional settings required  
for coding and decoding.  
6.1.1. Clock Multiplication (Si5316)  
The device accepts dual input clocks in the 19, 39, 78, 155, 311, or 622 MHz frequency range and generates a de-  
jittered output clock at the same frequency. The frequency range is set by the FRQSEL [1:0] pins, as shown in  
Table 13. Frequency Settings  
FRQSEL[1:0]  
Output Frequency (MHz)  
19.38–22.28  
LL  
LM  
LH  
38.75–44.56  
77.50–89.13  
ML  
MM  
MH  
155.00–178.25  
310.00–356.50  
620.00–710.00  
50  
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The Si5316 can accept a CKIN1 input at a different frequency than the CKIN2 input. The frequency of one input  
clock can be 1x, 4x, or 32x the frequency of the other input clock. The output frequency is always equal to the lower  
of the two clock inputs and is set via the FRQSEL [1:0] pins. The frequency applied at each clock input is divided  
down by a pre-divider as shown in the Figure 1 on page 17. These pre-dividers must be set such that the two  
resulting clock frequencies, f3_1 and f3_2 must be equal and are set by the FRQSEL [1:0] pins. Input divider  
settings are controlled by the CK1DIV and CK2DIV pins, as shown in Table 14.  
Table 14. Input Divider Settings  
CKnDIV  
N3n Input Divider  
L
M
H
1
4
32  
Table 15. Si5316 Bandwidth Values  
FRQSEL[1:0] Nominal Frequency Values (MHz)  
LL  
LM  
LH  
ML  
MM  
MH  
BW[1:0]  
HM  
19.44 MHz 38.88 MHz 77.76 MHz 155.52 MHz 311.04 MHz 622.08 MHz  
100 Hz  
210 Hz  
410 Hz  
1.7 kHz  
7.0 kHz  
100 Hz  
210 Hz  
410 Hz  
1.7 kHz  
7.0 kHz  
100 Hz  
200 Hz  
400 Hz  
1.6 kHz  
6.8 kHz  
100 Hz  
200 Hz  
400 Hz  
1.6 kHz  
6.7 kHz  
100 Hz  
200 Hz  
400 Hz  
1.6 kHz  
6.7 kHz  
100 Hz  
200 Hz  
400 Hz  
1.6 kHz  
6.7 kHz  
HL  
MH  
MM  
ML  
One-to-one  
frequency ratio  
1, 4, 32  
CKIN1  
CKIN2  
f3  
Fout  
DSPLL  
f3 = Fout  
1, 4, 32  
Figure 24. Si5316 Divisor Ratios  
Rev. 0.5  
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6.1.2. Clock Multiplication (Si5322, Si5323, Si5365, Si5366)  
These parts provide flexible frequency plans for SONET, DATACOM, and interworking between the two (Table 16,  
Table 17, and Table 18 respectively). The CKINn inputs must be the same frequency as specified in the tables. The  
outputs are the same frequency; however, in the Si5365 and Si5366, CKOUT3 and CKOUT4 can be further divided  
down by using the DIV34 [1:0] pins.  
The following notes apply to Tables 16, 17, and 18:  
1. All entries are available for the Si5323 and Si5366. Only those marked entries under the WB column are  
available for the Si5322 and Si5365.  
2. The listed output frequencies appear on CKOUTn. For the Si5365 and Si5366, sub-multiples are available on  
CKOUT3 and CKOUT4 using the DIV34[1:0] control pins.  
3. All ratios are exact, but the frequency values are rounded.  
4. For bandwidth settings, f3 values, and frequency operating ranges, consult DSPLLsim.  
5. For the Si5366 with CK_CONF = 1, CKIN3 and CKIN4 are the same frequency as FS_OUT.  
Table 16. SONET Clock Multiplication Settings (FRQTBL=L)  
No  
FRQSEL  
[3:0]  
f
MHz  
Mult Factor  
Nominal  
MHz  
All Devices  
(MHz)  
Si5366 Only  
IN  
f
OUT  
f
FS_OUT (MHz)  
(CK_CONF = 1)  
CKOUT5  
(CK_CONF = 0)  
0
1
2
3
4
5
6
LLLL  
LLLM  
LLLH  
LLML  
LLMM  
LLMH  
LLHL  
0.008  
1
0.008  
0.008  
0.008  
0.008  
0.008  
0.008  
0.008  
0.008  
0.008  
2430  
4860  
9720  
19440  
38880  
77760  
19.44  
38.88  
19.44  
38.88  
77.76  
77.76  
155.52  
311.04  
622.08  
155.52  
311.04  
622.08  
52  
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Table 16. SONET Clock Multiplication Settings (FRQTBL=L) (Continued)  
No  
FRQSEL  
[3:0]  
f
MHz  
Mult Factor  
Nominal  
MHz  
All Devices  
(MHz)  
Si5366 Only  
IN  
f
OUT  
f
FS_OUT (MHz)  
(CK_CONF = 1)  
CKOUT5  
(CK_CONF = 0)  
7
8
LLHM  
LLHH  
LMLL  
LMLM  
19.44  
1
2
4
8
19.44  
19.44  
0.008  
0.008  
0.008  
0.008  
38.88  
77.76  
38.88  
77.76  
9
10  
155.52  
155.52  
11  
12  
13  
14  
LMLH  
LMML  
LMMM  
LMMH  
8 x (255/238)  
8 x (255/237)  
8 x (255/236)  
16  
166.63  
167.33  
168.04  
311.04  
166.63  
167.33  
168.04  
311.04  
NA  
NA  
NA  
0.008  
15  
LMHL  
32  
622.08  
622.08  
0.008  
16  
17  
18  
19  
LMHM  
LMHH  
LHLL  
32 x (255/238)  
32 x (255/237)  
32 x (255/236)  
48  
666.51  
669.33  
672.16  
933.12  
666.51  
669.33  
672.16  
933.12  
NA  
NA  
NA  
LHLM  
0.008  
20  
21  
22  
23  
24  
LHLH  
LHML  
LHMM  
LHMH  
LHHL  
54  
1
1049.76  
38.88  
1049.76  
38.88  
0.008  
0.008  
0.008  
0.008  
0.008  
38.88  
2
77.76  
77.76  
4
155.52  
622.08  
155.52  
622.08  
16  
25  
26  
27  
LHHM  
LHHH  
MLLL  
16 x (255/238)  
16 x (255/237)  
16 x (255/236)  
666.51  
669.33  
672.16  
666.51  
669.33  
672.16  
NA  
NA  
NA  
Rev. 0.5  
53  
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Table 16. SONET Clock Multiplication Settings (FRQTBL=L) (Continued)  
No  
FRQSEL  
[3:0]  
f
MHz  
Mult Factor  
Nominal  
MHz  
All Devices  
(MHz)  
Si5366 Only  
IN  
f
OUT  
f
FS_OUT (MHz)  
(CK_CONF = 1)  
CKOUT5  
(CK_CONF = 0)  
28  
29  
30  
31  
32  
MLLM  
MLLH  
MLML  
MLMM  
MLMH  
77.76  
1/4  
19.44  
19.44  
0.008  
0.008  
0.008  
0.008  
NA  
1/2  
38.88  
77.76  
38.88  
77.76  
1
2
155.52  
166.63  
155.52  
166.63  
2 x (255/238)  
33  
34  
35  
MLHL  
MLHM  
MLHH  
2 x (255/237)  
2 x (255/236)  
4
167.33  
168.04  
311.04  
167.33  
168.04  
311.04  
NA  
NA  
0.008  
36  
37  
MMLL  
MMLM  
8
622.08  
666.51  
622.08  
666.51  
0.008  
NA  
8 x (255/238)  
38  
39  
40  
MMLH  
MMML  
MMMM  
8 x (255/237)  
8 x (255/236)  
1/8  
669.33  
672.16  
19.44  
669.33  
672.16  
19.44  
NA  
NA  
155.52  
0.008  
41  
42  
43  
44  
MMMH  
MMHL  
MMHM  
MMHH  
1/4  
1/2  
38.88  
77.76  
38.88  
77.76  
0.008  
0.008  
0.008  
NA  
1
155.52  
166.63  
155.52  
166.63  
255/238  
45  
46  
47  
MHLL  
MHLM  
MHLH  
255/237  
255/236  
2
167.33  
168.04  
311.04  
167.33  
168.04  
311.04  
NA  
NA  
0.008  
48  
49  
MHML  
MHMM  
4
622.08  
666.51  
622.08  
666.51  
0.008  
NA  
4 x (255/238)  
50  
51  
52  
MHMH  
MHHL  
MHHM  
4 x (255/237)  
4 x (255/236)  
238/255  
669.33  
672.16  
155.52  
669.33  
672.16  
155.52  
NA  
NA  
NA  
166.63  
53  
54  
55  
MMHM  
MHHH  
MHML  
1
166.63  
622.08  
666.51  
166.63  
622.08  
666.51  
NA  
NA  
NA  
4 x (238/255)  
4
54  
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Table 16. SONET Clock Multiplication Settings (FRQTBL=L) (Continued)  
No  
FRQSEL  
[3:0]  
f
MHz  
Mult Factor  
Nominal  
MHz  
All Devices  
(MHz)  
Si5366 Only  
IN  
f
OUT  
f
FS_OUT (MHz)  
(CK_CONF = 1)  
CKOUT5  
(CK_CONF = 0)  
56  
57  
HLLL  
167.33  
168.04  
311.04  
237/255  
1
155.52  
167.33  
155.52  
NA  
NA  
MMHM  
167.33  
58  
59  
HLLM  
4 x (237/255)  
4
622.08  
669.33  
622.08  
669.33  
NA  
NA  
MHML  
60  
61  
HLLH  
236/255  
1
155.52  
168.04  
155.52  
168.04  
NA  
NA  
MMHM  
62  
63  
HLML  
4 x (236/255)  
4
622.08  
672.16  
622.08  
672.16  
NA  
NA  
MHML  
64  
65  
66  
HLMM  
HLMH  
HLHL  
1
311.04  
622.08  
666.51  
311.04  
622.08  
666.51  
0.008  
0.008  
NA  
2
2 x (255/238)  
67  
68  
69  
HLHM  
HLHH  
HMLL  
2 x (255/237)  
2 x (255/236)  
1/32  
669.33  
672.16  
19.44  
669.33  
672.16  
19.44  
NA  
NA  
622.08  
0.008  
70  
71  
72  
73  
74  
75  
HMLM  
HMLH  
HMML  
HMMM  
HMMH  
HMHL  
1/16  
1/8  
38.88  
77.76  
38.88  
77.76  
0.008  
0.008  
0.008  
0.008  
0.008  
NA  
1/4  
155.52  
311.04  
622.08  
666.51  
155.52  
311.04  
622.08  
666.51  
1/2  
1
255/238  
76  
77  
HMHM  
HMHH  
255/237  
255/236  
669.33  
672.16  
669.33  
672.16  
NA  
NA  
78  
79  
80  
81  
HHLL  
HMML  
HHLM  
HMMH  
666.51  
1/4 x 238/255  
155.52  
166.63  
622.08  
666.51  
155.52  
166.63  
622.08  
666.51  
NA  
NA  
NA  
NA  
1/4  
238/255  
1
Rev. 0.5  
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Table 16. SONET Clock Multiplication Settings (FRQTBL=L) (Continued)  
No  
FRQSEL  
[3:0]  
f
MHz  
Mult Factor  
Nominal  
MHz  
All Devices  
(MHz)  
Si5366 Only  
IN  
f
OUT  
f
FS_OUT (MHz)  
(CK_CONF = 1)  
CKOUT5  
(CK_CONF = 0)  
82  
83  
HHLH  
HMML  
669.33  
672.16  
1/4 x 237/255  
1/4  
155.52  
167.33  
155.52  
NA  
NA  
167.33  
84  
85  
HHML  
HMMH  
237/255  
1
622.08  
669.33  
622.08  
669.33  
NA  
NA  
86  
87  
HHMM  
HMML  
1/4 x 236/255  
1/4  
155.52  
168.04  
155.52  
168.04  
NA  
NA  
88  
89  
HHMH  
HMMH  
236/255  
1
622.08  
672.16  
622.08  
672.16  
NA  
NA  
56  
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Table 17. Datacom Clock Multiplication Settings (FRQTBL = M, CK_CONF = 0)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
0
1
2
3
4
5
LLLL  
LLLM  
LLLH  
LLML  
LLMM  
LLMH  
15.625  
2
4
31.25  
62.5  
125  
8
16  
17/4  
5
250  
25  
106.25  
125  
6
7
LLHL  
LLHM  
LLHH  
LMLL  
LMLM  
LMLH  
LMML  
25/4 x 66/64  
51/8 x 66/64  
161.13  
164.36  
172.64  
173.37  
176.1  
8
25/4 x 66/64 x 255/238  
25/4 x 66/64 x 255/237  
51/8 x 66/64 x 255/238  
51/8 x 66/64 x 255/237  
17/2  
9
10  
11  
12  
176.84  
212.5  
13  
LMMM  
17  
425  
14  
15  
16  
17  
18  
19  
20  
LMMH  
LMHL  
LMHM  
LMHH  
LHLL  
25 x 66/64  
51/2 x 66/64  
644.53  
657.42  
690.57  
693.48  
704.38  
707.35  
62.5  
25 x 66/64 x 255/238  
25 x 66/64 x 255/237  
51/2 x 66/64 x 255/238  
51/2 x 66/64 x 255/237  
2
LHLM  
LHLH  
31.25  
53.125  
106.25  
21  
22  
23  
24  
25  
26  
LHML  
LHMM  
LHMH  
LHHL  
LHHM  
LHHH  
4
125  
250  
8
2
106.25  
212.5  
425  
4
8
3/2 x 66/64  
164.36  
27  
28  
29  
MLLL  
MLLM  
MLLH  
3/2 x 66/64 x 255/238  
3/2 x 66/64 x 255/237  
2
176.1  
176.84  
212.5  
30  
31  
MLML  
MLMM  
4
425  
6 x 66/64  
657.42  
32  
33  
MLMH  
MLHL  
6 x 66/64 x 255/238  
6 x 66/64 x 255/237  
704.38  
707.35  
Rev. 0.5  
57  
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Table 17. Datacom Clock Multiplication Settings (FRQTBL = M, CK_CONF = 0) (Continued)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
34  
MLHM  
125  
10/8 x 66/64  
161.13  
35  
36  
37  
MLHH  
MMLL  
MMLM  
10/8 x 66/64 x 255/238  
10/8 x 66/64 x 255/237  
5 x 66/64  
172.64  
173.37  
644.53  
38  
39  
40  
MMLH  
MMML  
MMMM  
5 x 66/64 x 255/238  
5 x 66/64 x 255/237  
66/64  
690.57  
693.48  
161.13  
156.25  
41  
42  
43  
MMMH  
MMHL  
MMHM  
66/64 x 255/238  
66/64 x 255/237  
4 x 66/64  
172.64  
173.37  
644.53  
44  
45  
46  
MMHH  
MHLL  
4 x 66/64 x 255/238  
4 x 66/64 x 255/237  
66/64  
690.57  
693.48  
164.36  
MMMM  
159.375  
47  
48  
49  
MMMH  
MMHL  
MMHM  
66/64 x 255/238  
66/64 x 255/237  
4 x 66/64  
176.1  
176.84  
657.4  
50  
51  
52  
MMHH  
MHLL  
MHLM  
4 x 66/64 x 255/238  
4 x 66/64 x 255/237  
4/5 x 64/66  
704.38  
707.35  
125  
161.13  
53  
MHLH  
255/238  
172.64  
54  
55  
MHML  
MHMM  
255/237  
4
173.37  
644.53  
56  
MHMH  
4 x 255/238  
690.57  
57  
58  
59  
MHHL  
MHHM  
MHLH  
4 x 255/237  
2/3 x 64/66  
255/238  
693.48  
106.25  
176.1  
164.36  
172.64  
60  
61  
MHML  
MHMM  
255/237  
4
176.84  
657.42  
62  
MHMH  
4 x 255/238  
704.38  
63  
64  
65  
66  
MHHL  
MHHH  
HLLL  
4 x 255/237  
4/5 x 64/66 x 238/255  
64/66 x 238/255  
238/255  
707.35  
125  
156.25  
161.13  
HLLM  
67  
68  
HLLH  
4 x 238/255  
4
644.53  
690.57  
MHMM  
58  
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Table 17. Datacom Clock Multiplication Settings (FRQTBL = M, CK_CONF = 0) (Continued)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
69  
70  
71  
HLML  
HLMM  
HLMH  
173.37  
4/5 x 64/66 x 237/255  
64/66 x 237/255  
237/255  
125  
156.25  
161.13  
72  
73  
HLHL  
4 x 237/255  
4
644.53  
693.48  
MHMM  
74  
75  
76  
HLHM  
HLLL  
HLLM  
176.1  
2/3 x 64/66 x 238/255  
64/66 x 238/255  
238/255  
106.25  
159.375  
164.36  
77  
78  
HLLH  
4 x 238/255  
4
657.42  
704.38  
MHMM  
79  
80  
81  
HLHH  
HLMM  
HLMH  
176.84  
2/3 x 64/66 x 237/255  
64/66 x 237/255  
237/255  
106.25  
159.375  
164.36  
82  
83  
HLHL  
4 x 237/255  
4
657.42  
707.35  
MHMM  
84  
85  
86  
87  
88  
89  
HMLL  
HMLM  
HMLH  
HMML  
HMMM  
HMMH  
212.5  
425  
2
425  
425  
1
1/5 x 64/66  
1/4  
644.53  
125  
161.13  
644.53  
690.57  
1
255/238  
90  
91  
HMHL  
HMHM  
255/237  
693.48  
106.25  
657.42  
690.57  
1/6 x 64/66  
92  
93  
94  
HMML  
HMMM  
HMMH  
1/4  
1
164.36  
657.42  
704.38  
255/238  
95  
96  
97  
HMHL  
HMHH  
HHLL  
255/237  
707.35  
125  
1/5 x 64/66 x 238/255  
1/4 x 64/66 x 238/255  
156.25  
98  
99  
HHLM  
HMML  
HHLH  
HMMM  
1/4 x 238/255  
161.13  
172.64  
644.53  
690.57  
1/4  
238/255  
1
100  
101  
Rev. 0.5  
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Table 17. Datacom Clock Multiplication Settings (FRQTBL = M, CK_CONF = 0) (Continued)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
102  
103  
104  
HHML  
HHMM  
HHMH  
693.48  
1/5 x 64/66 x 237/255  
1/4 x 64/66 x 237/255  
1/4 x 237/255  
125  
156.25  
161.13  
105  
HMML  
1/4  
173.37  
106  
107  
HHHL  
237/255  
1
644.53  
693.48  
HMMM  
108  
109  
110  
HHHM  
HHLL  
HHLM  
704.38  
1/6 x 64/66 x 238/255  
1/4 x 64/66 x 238/255  
1/4 x (238/255)  
106.25  
159.375  
164.36  
111  
112  
113  
HMML  
HHLH  
1/4  
238/255  
1
176.1  
657.42  
704.38  
HMMM  
114  
115  
116  
HHHH  
HHMM  
HHMH  
707.35  
1/6 x 64/66 x 237/255  
1/4 x 64/66 x 237/255  
1/4 x (237/255)  
106.25  
159.375  
164.36  
117  
HMML  
1/4  
176.84  
118  
119  
HHHL  
237/255  
1
657.42  
707.35  
HMMM  
60  
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Table 18. SONET to Datacom Clock Multiplication Settings  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
0
1
LLLL  
LLLM  
LLLH  
0.008  
3125  
6480  
25  
51.84  
53.125  
62.5  
2
53125/8  
3
LLML  
LLMM  
LLMH  
LLHL  
15625/2  
4
53125/4  
106.25  
125  
5
15625  
6
78125/4  
156.25  
159.375  
212.5  
425  
7
LLHM  
LLHH  
LMLL  
LMLM  
LMLH  
LMML  
LMMM  
LMMH  
LMHL  
LMHM  
LMHH  
LHLL  
159375/8  
53125/2  
8
9
53125  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
19.440  
625/486  
25  
10625/3888  
3125/972  
10625/1944  
3125/486  
15625/1944  
31875/3888  
15625/1944 x 66/64  
31875/3888 x 66/64  
53.125  
62.5  
106.25  
125  
156.25  
159.375  
161.13  
164.36  
172.64  
LHLM  
15625/1944 x 66/  
64 x 255/238  
20  
LHLH  
31875/3888 x 66/  
64 x 255/238  
176.1  
21  
22  
23  
24  
25  
LHML  
LHMM  
LHMH  
LHHL  
LHHM  
10625/972  
10625/486  
212.5  
425  
15625/486 x 66/64  
31875/972 x 66/64  
644.53  
657.42  
690.57  
15625/486 x 66/  
64 x 255/238  
26  
LHHH  
31875/972 x 66/  
64 x 255/238  
704.38  
27  
28  
29  
MLLL  
MLLM  
MLLH  
27.000  
1
27  
250/91  
11/4  
74.17582  
74.25  
Rev. 0.5  
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Table 18. SONET to Datacom Clock Multiplication Settings (Continued)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
30  
31  
MLML  
62.500  
74.176  
2
4
125  
250  
MLMM  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
MLMH  
MLHL  
91/250  
1
27  
74.17582  
74.25  
MLHM  
MLHH  
MMLL  
MMLM  
MMLH  
MMML  
MMMM  
MMMH  
MMHL  
MMHM  
MMHH  
91 x 11/250 x 4  
4/11  
74.250  
77.760  
27  
4 x 250/11 x 91  
1
74.17582  
74.25  
10625/7776  
3125/1944  
15625/7776  
31875/15552  
15625/7776 x 66/64  
31875/15552 x 66/64  
106.25  
125  
156.25  
159.375  
161.13  
164.36  
172.64  
15625/7776 x 66/  
64 x 255/238  
45  
MHLL  
31875/15552 x 66/  
64 x 255/238  
176.1  
46  
47  
48  
49  
50  
MHLM  
MHLH  
MHML  
MHMM  
MHMH  
10625/3888  
10625/1944  
212.5  
425  
15625/1944 x 66/64  
31875/3888 x 66/64  
644.53  
657.42  
690.57  
15625/1944 x 66/  
64 x 255/238  
51  
MHHL  
31875/3888 x 66/  
64 x 255/238  
704.38  
62  
Rev. 0.5  
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Table 18. SONET to Datacom Clock Multiplication Settings (Continued)  
Setting FRQSEL[3:0]  
f
(MHz)  
Mult Factor  
f
* (MHz)  
OUT  
IN  
52  
53  
54  
55  
56  
MHHM  
MHHH  
HLLL  
155.520  
15625/15552  
31875/31104  
156.25  
159.375  
161.13  
164.36  
172.64  
15625/15552 x 66/64  
31875/31104 x 66/64  
HLLM  
HLLH  
15625/15552 x 66/  
64 x 255/238  
57  
HLML  
31875/31104 x 66/  
64 x 255/238  
176.1  
58  
59  
60  
61  
62  
HLMM  
HLMH  
HLHL  
HLHM  
HLHH  
10625/7776  
10625/3888  
212.5  
425  
15625/3888 x 66/64  
31875/7776 x 66/64  
644.53  
657.42  
690.57  
15625/3888 x 66/  
64 x 255/238  
63  
HMLL  
31875/7776 x 66/  
64 x 255/238  
704.38  
64  
65  
66  
HMLM  
HMLH  
HMML  
622.080  
15625/15552 x 66/64  
31875/31104 x 66/64  
644.53  
657.42  
690.57  
15625/15552 x 66/  
64 x 255/238  
67  
HMMM  
31875/31104 x 66/  
64 x 255/238  
704.38  
Rev. 0.5  
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6.1.3. CKOUT3 and CKOUT4 (Si5365 and Si5366)  
Submultiples of the output frequency on CKOUT1 and CKOUT2 can be produced on the CKOUT3 and CKOUT4  
outputs using the DIV34 [1:0] control pins as shown in Table 19.  
Table 19. Clock Output Divider Control (DIV34)  
DIV34[1:0]  
HH  
Output Divider Value  
32  
16  
10  
8
HM  
HL  
MH  
MM  
ML  
6
5
LH  
4
LM  
2
LL  
1
6.1.4. Loop bandwidth (Si5316, Si5322, Si5323, Si5365, Si5366)  
The loop bandwidth (BW) is digitally programmable using the BWSEL [1:0] input pins. The device operating  
frequency should be determined prior to loop bandwidth configuration because the loop bandwidth is a function of  
the phase detector input frequency and the PLL feedback divider setting. Use DSPLLsim to calculate these values  
automatically. This utility is available for download from www.silabs.com/timing.  
6.1.5. Jitter Tolerance (Si5316, Si5323, Si5366)  
6.1.6. Narrowband Performance (Si5316, Si5323, Si5366)  
The DCO uses the reference clock on the XA/XB pins as its reference for jitter attenuation. The XA/XB pins support  
either a crystal oscillator or an input buffer (single-ended or differential) so that an external oscillator can be used  
as the reference source. The reference source is chosen with the RATE [1:0] pins. In both cases, there are wide  
margins in the absolute frequency of the reference input because it is a fixed frequency reference and is only used  
as a jitter reference and holdover reference (see "6.4. Digital Hold/VCO Freeze" on page 70).  
However, care must be taken in certain areas for optimum performance. For details on this subject, refer to  
Si5368, Si5369, Si5374, Si5375)" on page 121. For examples of connections to the XA/XB pins, refer to "8.4.  
6.1.7. Input-to-Output Skew (Si5316, Si5323, Si5366)  
The input-to-output skew for these devices is not controlled.  
6.1.8. Wideband Performance (Si5322 and Si5365)  
These devices operate as wideband clock multipliers without an external resonator or reference clock. They are  
ideal for applications where the input clock is already low jitter and only simple clock multiplication is required. A  
limited selection of clock multiplication factors is available (See Table 16, Table 17, and Table 18).  
6.1.9. Lock Detect (Si5322 and Si5365)  
A PLL loss of lock indicator is not available in these parts.  
6.1.10. Input-to-Output Skew (Si5322 and Si5365)  
The input-to-output skew for these devices is not controlled.  
64  
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6.2. PLL Self-Calibration  
An internal self-calibration (ICAL) is performed before operation to optimize loop parameters and jitter  
performance. While the self-calibration is being performed, the DSPLL is being internally controlled by the self-  
calibration state machine, and the LOL alarm will be active for narrowband parts. The self-calibration time t  
LOCKHW  
Any of the following events will trigger a self-calibration:  
Power-on-reset (POR)  
Release of the external reset pin RST (transition of RST from 0 to 1)  
Change in FRQSEL, FRQTBL, BWSEL, or RATE pins  
Internal DSPLL registers out-of-range, indicating the need to relock the DSPLL.  
In any of the above cases, an internal self-calibration will be initiated if a valid input clock exists (no input alarm)  
and is selected as the active clock at that time. For the Si5316, Si5323 and Si5366, the external crystal or  
reference clock must also be present for the self-calibration to begin. If valid clocks are not present, the self-  
calibration state machine will wait until they appear, at which time the calibration will start. All outputs are on during  
the calibration process.  
After a successful self-calibration has been performed with a valid input clock, no subsequent self-calibrations are  
performed unless one of the above conditions are met. If the input clock is lost following self-calibration, the device  
enters digital hold mode. When the input clock returns, the device relocks to the input clock without performing a  
self-calibration. (Narrow band devices only).  
6.2.1. Input Clock Stability during Internal Self-Calibration (Si5316, Si5322, Si5323, Si5365, Si5366)  
An exit from reset must occur when the selected CKINn clock is stable in frequency with a frequency value that is  
within the operating range that is reported by DSPLLsim. The other CKINs must also either be stable in frequency  
or squelched during a reset.  
6.2.2. Self-Calibration caused by Changes in Input Frequency (Si5316, Si5322, Si5323, Si5365, Si5366)  
If the selected CKINn varies by 500 ppm or more in frequency since the last calibration, the device may initiate a  
self-calibration.  
6.2.3. Recommended Reset Guidelines (Si5316, Si5322, Si5323, Si5365, Si5366)  
Follow the recommended RESET guidelines in Table 20 and Table 21 when reset should be applied to a device.  
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Table 20. Si5316, Si5322, and Si5323 Pins and Reset  
Pin #  
Si5316 Pin  
Name  
Si5322 Pin  
Name  
Si5323 Pin  
Name  
Must Reset after Changing  
2
N/A  
RATE 0  
DBL_BY  
RATE1  
N/A  
FRQTBL  
N/A  
FRQTBL  
RATE 0  
Yes  
11  
14  
15  
19  
20  
22  
23  
24  
25  
26  
27  
30  
33  
Yes  
DBL2_BY  
N/A  
DBL2_BY  
RATE1  
No  
Yes  
N/A  
DEC  
No  
N/A  
N/A  
INC  
No  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
N/A  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
N/A  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
SFOUT0  
Yes  
Yes  
Yes  
Yes  
Yes  
N/A  
Yes  
SFOUT1  
SFOUT0  
No, but skew not guaranteed without Reset  
No, but skew not guaranteed without Reset  
N/A  
Table 21. Si5365 and Si5366 Pins and Reset  
Pin #  
4
Si5365 Pin Name  
FRQTBL  
N/A  
Si5366 Pin Name  
FRQTBL  
RATE 0  
Must Reset after Changing  
Yes  
32  
42  
51  
54  
55  
60  
61  
66  
67  
68  
69  
70  
71  
80  
95  
Yes  
N/A  
RATE 1  
Yes  
N/A  
CK_CONF  
DEC  
Yes  
N/A  
No  
N/A  
INC  
No  
BWSEL0  
BWSEL1  
DIV34_0  
DIV34_1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
N/A  
BSWEL0  
BWSEL1  
DIV34_0  
DIV34_1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
SFOUT0  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
No, but skew not guaranteed without Reset  
No, but skew not guaranteed without Reset  
N/A  
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6.3. Pin Control Input Clock Control  
This section describes the clock selection capabilities (manual input selection, automatic input selection, hitless  
switching, and revertive switching). When switching between two clocks, LOL may temporarily go high if the two  
clocks differ in frequency by more than 100 ppm.  
6.3.1. Manual Clock Selection  
Manual control of input clock selection is chosen via the CS[1:0] pins according to Table 22 and Table 23.  
Table 22. Manual Input Clock Selection (Si5316, Si5322, Si5323), AUTOSEL = L  
CS (Si5316)  
Si5316  
Si5322  
Si5323  
CS_CA (Si5322, Si5323)  
0
1
CKIN1  
CKIN2  
The manual input clock selection settings for the Si5365 and the Si5366 are shown in Table 23. The Si5366 has  
two modes of operation (See Section “6.5. Frame Synchronization (Si5366)”). With CK_CONF = 0, any of the four  
input clocks may be selected manually; however, when CK_CONF = 1 the inputs are paired, CKIN1 is paired with  
CKIN3 and likewise for CKIN2 and CKIN4. Therefore, only two settings are available to select one of the two pairs.  
Table 23. Manual Input Clock Selection (Si5365, Si5366), AUTOSEL = L  
[CS1_CA4, CS0_CA3]_Pins  
Si5365  
Si5366  
CK_CONF = 0  
CK_CONF = 1  
(5 Output Clocks) (FS_OUT Configuration)  
00  
01  
10  
11  
CKIN1  
CKIN2  
CKIN3  
CKIN4  
CKIN1  
CKIN2  
CKIN3  
CKIN4  
CKIN1/CKIN3  
CKIN2/CKIN4  
Reserved  
Reserved  
Notes:  
1. To avoid clock switching based on intermediate states during a CS state change, the CS input pins are  
internally deglitched.  
2. If the selected clock enters an alarm condition, the PLL enters digital hold mode.  
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6.3.2. Automatic Clock Selection (Si5322, Si5323, Si5365, Si5366)  
The AUTOSEL input pin sets the input clock selection mode as shown in Table 24. Automatic switching is either  
revertive or non-revertive. Setting AUTOSEL to M or H, changes the CSn_CAm pins to output pins that indicate the  
state of the automatic clock selection (See Table 25 and Table 26). Digital hold is indicated by all CnB signals going  
high after a valid ICAL.  
Table 24. Automatic/Manual Clock Selection  
AUTOSEL  
Clock Selection Mode  
Manual (See Previous Section)  
Automatic Non-revertive  
Automatic Revertive  
L
M
H
Table 25. Clock Active Indicators (AUTOSEL = M or H) (Si5322 and Si5323)  
CS_CA  
Active Clock  
CKIN1  
0
1
CKIN2  
Table 26. Clock Active Indicators (AUTOSEL = M or H) (Si5365 and Si5367)  
CA1  
CA2  
CS0_CA3  
CS1_CA4 Active Clock  
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1
CKIN1  
CKIN2  
CKIN3  
CKIN4  
The prioritization of clock inputs for automatic switching is shown in Table 27 and Table 28. This priority is  
hardwired in the devices.  
Table 27. Input Clock Priority for Auto Switching (Si5322, Si5323)  
Priority  
Input Clocks  
CKIN1  
1
2
3
CKIN2  
Digital Hold  
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Table 28. Input Clock Priority for Auto Switching (Si5365, Si5366)  
Priority  
Input Clock Configuration  
Si5366  
Si5365  
4 Input Clocks  
(CK_CONF = 0)  
FSYNC Switching  
(CK_CONF = 1)  
CKIN1/CKIN3  
CKIN2/CKIN4  
N/A  
1
2
3
4
5
CKIN1  
CKIN2  
CKIN3  
CKIN4  
N/A  
Digital Hold  
Digital Hold  
At power-on or reset, the valid CKINn with the highest priority (1 being the highest priority) is automatically  
selected. If no valid CKINn is available, the device suppresses the output clocks and waits for a valid CKINn signal.  
If the currently selected CKINn goes into an alarm state, the next valid CKINn in priority order is selected. If no valid  
CKINn is available, the device enters Digital Hold.  
Operation in revertive and non- revertive is different when a signal becomes valid:  
Revertive (AUTOSEL = H):  
The device constantly monitors all CKINn. If a CKINn with a higher priority than  
the current active CKINn becomes valid, the active CKINn is changed to the  
CKINn with the highest priority.  
Non-revertive (AUTOSEL = M): The active clock does not change until there is an alarm on the active clock. The  
device will then select the highest priority CKINn that is valid. Once in digital hold,  
the device will switch to the first CKINn that becomes valid.  
6.3.3. Hitless Switching with Phase Build-Out (Si5323, Si5366)  
Silicon Laboratories switching technology performs “phase build-out” to minimize the propagation of phase  
transients to the clock outputs during input clock switching. All switching between input clocks occurs within the  
input multiplexor and phase detector circuitry. The phase detector circuitry continually monitors the phase  
difference between each input clock and the DSPLL output clock, f  
. The phase detector circuitry can lock to a  
OSC  
clock signal at a specified phase offset relative to f  
so that the phase offset is maintained by the PLL circuitry.  
OSC  
At the time a clock switch occurs, the phase detector circuitry knows both the input-to-output phase relationship for  
the original input clock and for the new input clock. The phase detector circuitry locks to the new input clock at the  
new clock's phase offset so that the phase of the output clock is not disturbed. The phase difference between the  
two input clocks is absorbed in the phase detector's offset value, rather than being propagated to the clock output.  
The switching technology virtually eliminates the output clock phase transients traditionally associated with clock  
rearrangement (input clock switching).  
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6.4. Digital Hold/VCO Freeze  
All Any-Frequency Precision Clock devices feature a hold over or VCO freeze mode, whereby the DSPLL is locked  
to a digital value.  
6.4.1. Narrowband Digital Hold (Si5316, Si5323, Si5366)  
If an LOS or FOS condition exists on the selected input clock, the device enters digital hold. In this mode, the  
device provides a stable output frequency until the input clock returns and is validated. When the device enters  
digital hold, the internal oscillator is initially held to its last frequency value. Next, the internal oscillator slowly  
transitions to a historical average frequency value that was taken over a time window of 6,711 ms in size that  
ended 26 ms before the device entered digital hold. This frequency value is taken from an internal memory location  
that keeps a record of previous DSPLL frequency values. By using a historical average frequency, input clock  
phase and frequency transients that may occur immediately preceding loss of clock or any event causing digital  
hold do not affect the digital hold frequency. Also, noise related to input clock jitter or internal PLL jitter is  
minimized.  
If a highly stable reference, such as an oven-controlled crystal oscillator, is supplied at XA/XB, an extremely stable  
digital hold can be achieved. If a crystal is supplied at the XA/XB port, the digital hold stability will be limited by the  
stability of the crystal.  
6.4.2. Recovery from Digital Hold (Si5316, Si5323, Si5366)  
When the input clock signal returns, the device transitions from digital hold to the selected input clock. The device  
performs hitless recovery from digital hold. The clock transition from digital hold to the returned input clock includes  
“phase buildout” to absorb the phase difference between the digital hold clock phase and the input clock phase.  
6.4.3. Wideband VCO Freeze (Si5322, Si5365)  
If an LOS condition exists on the selected input clock, the device freezes the VCO. In this mode, the device  
provides a stable output frequency until the input clock returns and is validated. When the device enters VCO  
freeze, the internal oscillator is initially held to its last frequency value.  
6.5. Frame Synchronization (Si5366)  
FSYNC is used in applications that require a synchronizing pulse that has an exact number of periods of a high-  
rate clock, Frame Synchronization is selected by setting CK_CONF = 1 and FRQTBL = L). In a typical frame  
synchronization application, CKIN1 and CKIN2 are high-speed input clocks from primary and secondary clock  
generation cards and CKIN3 and CKIN4 are their associated primary and secondary frame synchronization  
signals. The device generates four output clocks and a frame sync output FS_OUT. CKIN3 and CKIN4 control the  
phase of FS_OUT.  
The frame sync inputs supplied to CKIN3 and CKIN4 must be 8 kHz. Since the frequency of FS_OUT is derived  
from CKOUT2, CKOUT2 must be a standard SONET frequency (e.g. 19.44 MHz, 77.76 MHz). Table 16 lists the  
input frequency/clock multiplication ratio combinations supporting an 8 kHz output on FS_OUT.  
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6.6. Output Phase Adjust (Si5323, Si5366)  
Overall device skew (CKINn to CKOUT_n phase delay) is controllable via the INC and DEC input pins. A positive  
pulse applied at the INC pin increases the device skew by 1/f , one period of the DCO output clock. A pulse on  
OSC  
the DEC pin decreases the skew by the same amount. Since f  
is close to 5 GHz, the resolution of the skew  
OSC  
control is approximately 200 ps. Using the INC and DEC pins, there is no limit to the range of skew adjustment that  
can be made. Following a power-up or reset, the skew will revert to the reset value.  
The INC pin function is not available for all frequency table selections. DSPLLsim reports this whenever it is used  
to implement a frequency plan.  
6.6.1. FSYNC Realignment (Si5366)  
The FS_ALIGN pin controls the realignment of FS_OUT to the active CKIN3 or CKIN4 input. The currently active  
frame sync input is determined by which input clock is currently being used by the PLL. For example, if CKIN1 is  
being selected as the PLL input, CKIN3 is the currently-active frame sync input. If neither CKIN3 or CKIN4 are  
currently active (digital hold), the realignment request is ignored. The active edge used for realignment is the  
CKIN3 or CKIN4 rising edge.  
FS_ALIGN operates in Level Sensitive mode (See Figure 19, “Frame Synchronization Timing.”). While FS_ALIGN  
is active, each active edge of the currently-active frame sync input (CKIN3 or CKIN4) is used to control the NC5  
output divider and therefore the FS_OUT phase. Note that while the realignment control is active, it cannot be  
guaranteed that a fixed number of high-frequency clock (CKOUT2) cycles exists between each FS_OUT cycle.  
The resolution of the phase realignment is 1 clock cycle of CKOUT2. If the realignment control is not active, the  
NC5 divider will continuously divide down its f  
input. This guarantees a fixed number of high-frequency  
CKOUT2  
clock (CKOUT2) cycles between each FS_OUT cycle.  
At power-up or any time after the PLL has lost lock and relocked, the device automatically performs a realignment  
of FS_OUT using the currently active sync input. After this, as long as the PLL remains in lock and a realignment is  
not requested, FS_OUT will include a fixed number of high-speed clock cycles, even if input clock switches are  
performed. If many clock switches are performed in phase build-out mode, it is possible that the input sync to  
output sync phase relationship will shift due to the accumulated residual phase transients of the phase build-out  
circuitry. If the sync alignment error exceeds the threshold in either the positive or negative direction, an alignment  
alarm becomes active. If it is then desired to reestablish the desired input-to-output sync phase relationship, a  
realignment can be performed. A realignment request may cause FS_OUT to instantaneously shift its output edge  
location in order to align with the active input sync phase.  
6.6.2. Including FSYNC Inputs in Clock Selection (Si5366)  
The frame sync inputs, CKIN3 and CKIN4, are both monitored for loss-of-signal (LOS3_INT and LOS4_INT)  
conditions. To include these LOS alarms in the input clock selection algorithm, set FS_SW = 1. The LOS3_INT is  
logically ORed with LOS1_INT and LOS4_INT is ORed with LOS2_INT as inputs to the clock selection state  
machine. If it is desired not to include these alarms in the clock selection algorithm, set FS_SW = 0. The FOS  
alarms for CKIN3 and CKIN4 are ignored. See Table 33 on page 74.  
6.6.3. FS_OUT Polarity and Pulse Width Control (Si5366)  
Additional output controls are available for FS_OUT. FS_OUT is active high, and the pulse width is equal to one  
period of the CKOUT2 output clock. For example, if CKOUT2 is 622.08 MHz, the FS_OUT pulse width will be 1/  
622.08e6 = 1.61 ns.  
6.6.4. Using FS_OUT as a Fifth Output Clock (Si5366)  
In applications where the frame synchronization functionality is not needed, FS_OUT can be used as a fifth clock  
output. In this case, no realignment requests should be made to the NC5 divider. (This is done by holding  
FS_ALIGN to 0 and CK_CONF = 0).  
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6.6.5. Disabling FS_OUT (Si5366)  
The FS_OUT maybe disabled via the DBLFS pin, see Table 29. The additional state (M) provided allows for  
FS_OUT to drive a CMOS load while the other clock outputs use a different signal format as specified by the  
SFOUT[1:0] pins.  
Table 29. FS_OUT Disable Control (DBLFS)  
DBLFS  
FS_OUT State  
Tri-State/Powerdown  
Active/CMOS Format  
Active/SFOUT[1:0] Format  
H
M
L
6.7. Output Clock Drivers  
The devices include a flexible output driver structure that can drive a variety of loads, including LVPECL, LVDS,  
CML, and CMOS formats. The signal format is selected jointly for all outputs using the SFOUT [1:0] pins, which  
modify the output common mode and differential signal swing. See Table 4, “DC Characteristics” for output driver  
specifications. The SFOUT [1:0] pins are three-level input pins, with the states designated as L (ground), M (V  
/
DD  
2), and H (V ).  
DD  
Table 30 shows the signal formats based on the supply voltage and the type of load being driven. For the CMOS  
setting (SFOUT = LH), both output pins drive single-ended in-phase signals and should be externally shorted  
together to obtain the drive strength specified in Table 4, “DC Characteristics”, see Section “8.2. Output Clock  
Table 30. Output Signal Format Selection (SFOUT)  
SFOUT[1:0]  
Signal Format  
CML  
HL  
HM  
LVDS  
LH  
CMOS  
LM  
Disabled  
LVPECL  
MH  
ML  
Low-swing LVDS  
Reserved  
All Others  
The SFOUT [1:0] pins can also be used to disable the output. Disabling the output puts the CKOUT+ and CKOUT–  
pins in a high-impedance state relative to V (common mode tri-state) while the two outputs remain connected to  
DD  
each other through a 200 on-chip resistance (differential impedance of 200 ). The maximum amount of internal  
circuitry is powered down, minimizing power consumption and noise generation. Changing SFOUT without a reset  
causes the output to output skew to become random. When SFOUT = LH for CMOS, PLL bypass mode is not  
supported.  
6.7.1. LVPECL and CMOS TQFP Output Signal Format Restrictions at 3.3 V (Si5365, Si5366)  
The LVPECL and CMOS output formats draw more current than either LVDS or CML. However, the allowed output  
format pin settings are restricted so that the maximum power dissipation for the TQFP devices is limited when they  
are operated at 3.3 V. When SFOUT[1:0] = MH or LH (for either LVPECL or CMOS), either DBL5 must be H or  
DBL34 must be high.  
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6.8. PLL Bypass Mode  
The device supports a PLL bypass mode in which the selected input clock is fed directly to all enabled output  
buffers, bypassing the DSPLL. In PLL bypass mode, the input and output clocks will be at the same frequency. PLL  
bypass mode is useful in a laboratory environment to measure system performance with and without the effects of  
jitter attenuation provided by the DSPLL.  
The DSBL2/BYPASS pin is used to select the PLL bypass mode according to Table 31.  
Table 31. DSBL2/BYPASS Pin Settings  
DSBL2/BYPASS  
Function  
CKOUT2 Enabled  
L
M
H
CKOUT2 Disabled  
PLL Bypass Mode w/ CKOUT2 Enabled  
Internally, the bypass path is implemented with high-speed differential signaling for low jitter. Bypass mode does  
not support CMOS clock output.  
6.9. Alarms  
Summary alarms are available to indicate the overall status of the input signals and frame alignment (Si5366 only).  
Alarm outputs stay high until all the alarm conditions for that alarm output are cleared.  
6.9.1. Loss-of-Signal Alarms (Si5316, Si5322, Si5323, Si5365, Si5366)  
The device has loss-of-signal circuitry that continuously monitors CKINn for missing pulses. The LOS circuitry  
generates an internal LOSn_INT output signal that is processed with other alarms to generate CnB.  
An LOS condition on CKIN1 causes the internal LOS1_INT alarm to become active. Similarly, an LOS condition on  
CKINn causes the LOSn_INT alarm to become active. Once a LOSn_INT alarm is asserted on one of the input  
clocks, it remains asserted until that input clock is validated over a designated time period. The time to clear  
LOSn_INT after a valid input clock appears is listed in Table 8, “AC Characteristics—All Devices”. If another error  
condition on the same input clock is detected during the validation time then the alarm remains asserted and the  
validation time starts over.  
6.9.1.1. Narrowband LOS Algorithm (Si5316, Si5323, Si5366)  
The LOS circuitry divides down each input clock to produce an 8 kHz to 2 MHz signal. (For the Si5316, the output  
of divider N3 (See Figure 1) is used.) The LOS circuitry over samples this divided down input clock using a 40 MHz  
clock to search for extended periods of time without input clock transitions. If the LOS monitor detects twice the  
normal number of samples without a clock edge, a LOSn_INT alarm is declared. Table 8, “AC Characteristics—All  
Devices” gives the minimum and maximum amount of time for the LOS monitor to trigger.  
6.9.1.2. Wideband LOS Algorithm (Si5322, Si5365)  
Each input clock is divided down to produce a 78 kHz to 1.2 MHz signal before entering the LOS monitoring  
circuitry. The same LOS algorithm as described in the above section is then used.  
6.9.2. FOS Alarms (Si5365 and Si5366)  
If FOS alarms are enabled (See Table 32), the internal frequency offset alarms (FOSn_INT) indicate if the input  
clocks are within a specified frequency band relative to the frequency of CKIN2. The frequency offset monitoring  
circuitry compares the frequency of the input clock(s) with CKIN2. If the frequency offset of an input clock exceeds  
a preset frequency offset threshold, an FOS alarm (FOSn_INT) is declared for that clock input. Note that FOS  
monitoring is not available on CKIN3 and CKIN4 if CK_CONF = 1. The device supports FOS hysteresis per GR-  
1244-CORE, making the device less susceptible to FOS alarm chattering. A TCXO or OCXO reference clock must  
be used in conjunction with either the SMC or Stratum 3/3E settings. Note that wander can cause false FOS  
alarms.  
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Table 32. Frequency Offset Control (FOS_CTL)  
FOS_CNTL  
Meaning  
L
M
H
FOS Disabled.  
Stratum 3/3E FOS Threshold (12 ppm)  
SONET Minimum Clock Threshold (48 ppm)  
6.9.3. FSYNC Align Alarm (Si5366 and CK_CONF = 1 and FRQTBL = L)  
At power-up or any time after the PLL has lost lock and relocked, the device automatically performs a realignment  
of FS_OUT using the currently active sync input. After this, as long as the PLL remains in lock and a realignment is  
not requested, FS_OUT will include a fixed number of high-speed clock cycles, even if input clock switches are  
performed. If many clock switches are performed, it is possible that the input sync to output sync phase relationship  
will shift due to the accumulated residual phase transients of the phase build-out circuitry. The internal ALIGN_INT  
signal is asserted when the accumulated phase errors exceeds two cycles of CKOUT2.  
6.9.4. C1B and C2B Alarm Outputs (Si5316, Si5322, Si5323)  
The alarm outputs (C1B and C2B) are determined directly by the LOS1_INT and LOS2_INT internal indicators  
directly. That is C1B = LOS1 and C2B = LOS2.  
6.9.5. C1B, C2B, C3B, and ALRMOUT Outputs (Si5365, Si5366)  
The alarm outputs (C1B, C2B, C3B, ALRMOUT) provide a summary of various alarm conditions on the input clocks  
depending on the setting of the FOS_CNTL and CK_CONF pins.  
The following internal alarm indicators are used in determining the output alarms:  
description of how LOSn_INT is determined  
FOSn_INT: See section “6.9.2. FOS Alarms (Si5365 and Si5366)”for a description of how FOSn_INT is  
determined  
description of how ALIGN_INT is determined  
Based on the above internal signals and the settings of the CK_CONF and FOS_CTL pins, the outputs C1B, C2B,  
C3B, ALRMOUT are determined (See Table 33). For details, see "Appendix D—Alarm Structure" on page 144.  
.
Table 33. Alarm Output Logic Equations  
CK_CONF  
FOS_CTL  
Alarm Output Equations  
0
L
C1B = LOS1_INT  
C2B = LOS2_INT  
C3B = LOS3_INT  
Four independent input (Disables FOS)  
clocks  
ALRMOUT = LOS4_INT  
M or H  
C1B = LOS1_INT or FOS1_INT  
C2B = LOS2_INT or FOS2_INT  
C3B = LOS3_INT or FOS3_INT  
ALRMOUT = LOS4_INT or FOS4_INT  
1
L
C1B = LOS1_INT or (LOS3_INT and FSYNC_SWTCH)  
C2B = LOS2_INT or (LOS4_INT and FSYNC_SWTCH)  
C3B = tri-state  
(FSYNC switching  
mode)  
(Disables FOS)  
ALRMOUT = ALIGN_INT  
M or H  
C1B = LOS1_INT or (LOS3_INT and FSYNC_SWTCH) or FOS1_INT  
C2B = LOS2_INT or (LOS4_INT and FSYNC_SWTCH) or FOS2_INT  
C3B = tri-state  
ALRMOUT = ALIGN_INT  
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6.9.5.1. PLL Lock Detect (Si5316, Si5323, Si5366)  
The PLL lock detection algorithm indicates the lock status on the LOL output pin. The algorithm works by  
continuously monitoring the phase of the input clock in relation to the phase of the feedback clock. If the time  
between two consecutive phase cycle slips is greater than the Retrigger Time, the PLL is in lock. The LOL output  
has a guaranteed minimum pulse width as shown in (Table 8, “AC Characteristics—All Devices”). The LOL pin is  
also held in the active state during an internal PLL calibration.  
The retrigger time is automatically set based on the PLL closed loop bandwidth (See Table 34).  
Table 34. Lock Detect Retrigger Time  
PLL Bandwidth Setting (BW)  
60–120 Hz  
Retrigger Time (ms)  
53  
120–240 Hz  
26.5  
13.3  
6.6  
240–480 Hz  
480–960 Hz  
960–1920 Hz  
3.3  
1920–3840 Hz  
3840–7680 Hz  
1.66  
.833  
6.9.5.2. Lock Detect (Si5322, Si5365)  
A PLL loss of lock indicator is not available for these devices.  
6.10. Device Reset  
Upon powerup, the device internally executes a power-on-reset (POR) which resets the internal device logic. The  
pin RST can also be used to initiate a reset. The device stays in this state until a valid CKINn is present, when it  
then performs a PLL Self-Calibration (See “6.2. PLL Self-Calibration”).  
6.11. DSPLLsim Configuration Software  
To simplify frequency planning, loop bandwidth selection, and general device configuration of the Any-Frequency  
Precision Clocks. Silicon Laboratories offers the DSPLLsim configuration utility for this purpose. This software is  
available to download from www.silabs.com/timing.  
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7. Microprocessor Controlled Parts (Si5319, Si5324, Si5325, Si5326, Si5327,  
Si5367, Si5368, Si5369, Si5374, Si5375)  
The devices in this family provide a rich set of clock multiplication/clock division options, loop bandwidth selections,  
output clock phase adjustment, and device control options.  
7.1. Clock Multiplication  
The input frequency, clock multiplication ratio, and output frequency are set via register settings. Because the  
DSPLL dividers settings are directly programmable, a wide range of frequency translations is available. In addition,  
a wider range of frequency translations is available in narrowband parts than wideband parts due to the lower  
phase detector frequency range in narrowband parts. To assist users in finding valid divider settings for a particular  
input frequency and clock multiplication ratio, Silicon Laboratories offers the DSPLLsim utility to calculate these  
settings automatically. When multiple divider combinations produce the same output frequency, the software  
recommends the divider settings that yield the best combination of phase noise performance and power  
consumption.  
7.1.1. Jitter Tolerance (Si5319, Si5324, Si5325, Si5326, Si5327, Si5368, Si5369, Si5374 and Si5375)  
See Section 5.2.3.  
7.1.2. Wideband Parts (Si5325, Si5367)  
These devices operate as wideband clock multipliers without an external resonator or reference clock. This mode  
may be desirable if the input clock is already low jitter and only simple clock multiplication is required. A limited  
selection of clock multiplication factors is available in this mode. The input-to-output skew for wideband parts is not  
controlled.  
Refer to Figure 25. The selected input clock passes through the N3 input divider and is provided to the DSPLL. The  
input-to-output clock multiplication ratio is defined as follows:  
f
= f x N2/(N1 x N3)  
IN  
OUT  
where:  
N1 = output divider  
N2 = feedback divider  
N3 = input divider  
fOUT = 2 kHz-1. 4 GHz  
fIN =10 MHz–710 MHz  
N1  
NC1  
4.85 – 5.67 GHz  
/
/
N31  
N32  
N33  
N34  
CKOUT_1  
CKOUT_2  
CKIN1  
CKIN2  
CKIN3  
CKIN4  
2
2
f3  
fOSC  
®
N1_HS  
DSPLL  
10 MHz–  
157.5 MHz  
/
/
NC2  
2
2
N2  
/
f3  
2
N2 =N2_LS  
N2_LS = [32, 34, 36, …, 512]  
/
/
NC5  
CKOUT_5  
2
2
NC1 =N1_ HS x N1_LS  
N1_ HS= [4,5,6,...,11]  
N1_ LS= [1,2,4,6,...,220]  
N3 =  
[1,2,3,...,219]  
Figure 25. Wideband PLL Divider Settings (Si5325, Si5367)  
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Because there is only one DCO and all of the outputs must be frequencies that are integer divisions of the DCO  
frequency, there are restrictions on the ratio of one output frequency to another output frequency. That is, there is  
considerable freedom in the ratio between the input frequency and the first output frequency; but once the first  
output frequency is chosen, there are restrictions on subsequent output frequencies. These restrictions are made  
tighter by the fact that the N1_HS divider is shared among all of the outputs. DSPLLsim should be used to  
determine if two different simultaneous outputs are compatible with one another.  
The same issue exists for inputs of different frequencies: both inputs, after having been divided by their respective  
N3 dividers, must result in the same f3 frequency because the phase/frequency detector can operate at only one  
frequency at one time.  
7.1.2.1. Loop Bandwidth (Si5325, Si5367)  
The loop bandwidth (BW) is digitally programmable using the BWSEL_REG[3:0] register bits. The device operating  
frequency should be determined prior to loop bandwidth configuration because the loop bandwidth is a function of  
the phase detector input frequency and the PLL feedback divider. See DSPLLsim for BWSEL_REG settings and  
associated bandwidth.  
7.1.2.2. Lock Detect (Si5325, Si5367)  
A PLL loss of lock indicator is not available in these devices.  
7.1.2.3. Input to Output Skew (Si5325, Si5367)  
The input to output skew for wideband devices is not controlled.  
7.1.3. Narrowband Parts (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
The DCO uses the reference clock on the XA/XB pins (OSC_P and OSC_N for the Si5374 and Si5375) as its  
reference for jitter attenuation. The XA/XB pins support either a crystal oscillator or an input buffer (single-ended or  
differential) so that an external oscillator can become the reference source. In both cases, there are wide margins  
in the absolute frequency of the reference input because it is a fixed frequency and is used only as a jitter reference  
119 for more details. The Si5374 and Si5375 must be used with an external crystal oscillator and cannot use  
crystals.  
Care must be exercised in certain areas for optimum performance. For details on this subject, refer to "Appendix  
Si5369, Si5374, Si5375)" on page 121. For examples of connections to the XA/XB (for the Si5374 and Si5375,  
Refer to Figure 26 Narrowband PLL Divider Settings (Si5319, Si5324, Si5326, Si5327, Si5368, Si5374, Si5375), a  
simplified block diagram of the device and Table 35 and Table 36 for frequency and divider limits. The PLL dividers  
and their associated ranges are listed in the diagram. Each PLL divider setting is programmed by writing to device  
registers. There are additional restrictions on the range of the input frequency f , the DSPLL phase detector clock  
IN  
rate f3, and the DSPLL output clock f  
.
OSC  
The selected input clock passes through the N3 input divider and is provided to the DSPLL. In addition, the  
external crystal or reference clock provides a reference frequency to the DSPLL. The DSPLL output frequency,  
f
, is divided down by each output divider to generate the clock output frequencies. The input-to-output clock  
OSC  
multiplication ratio is defined as follows:  
f
= f x N2/(N1 x N3)  
OUT  
IN  
where:  
N1 = output divider  
N2 = feedback divider  
N3 = input divider  
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Si53xx-RM  
Xtal, or Refclock  
(Si5319, Si5324, Si5326, Si5327, Si5368, Si5369;  
Refclock only for the Si5374 and Si5375)  
BYPASS  
2
2
CKIN_1+  
CKIN_1–  
÷ N31  
÷ N32  
1
0
CKOUT_1+  
CKOUT_1–  
2
2
2
2
2
÷ NC1  
fx  
CKIN_2+  
CKIN_2–  
Digital  
Phase  
Detector/  
Loop Filter  
f3  
fOSC  
1
0
CKOUT_2+  
CKOUT_2–  
M
÷ NC2  
÷ NC3  
÷ NC4  
÷ NC5  
÷ N1_HS  
DCO  
Si5368  
Si5369  
f3  
2
2
CKIN_3+  
CKIN_3–  
÷ N33  
÷ N34  
1
0
CKOUT_3+  
CKOUT_3–  
Si5368  
Si5369  
÷ N2_LS ÷ N2_HS  
CKIN_4+  
CKIN_4–  
1
0
CKOUT_4+  
CKOUT_4–  
1
0
CKOUT_5+  
CKOUT_5–  
Bandwidth  
Control  
FSYNC  
(Si5368)  
Note: See section 6.7  
for FSYNC details.  
Control  
SPI/I2C  
Si5319, Si5326,  
Si5368  
Note: There are multiple outputs at different frequencies because of limitations caused by the DCO and N1_HS.  
Figure 26. Narrowband PLL Divider Settings  
(Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
Table 35. Narrowband Frequency Limits  
Signal  
Frequency Limits  
2 kHz–710 MHz  
2 kHz–2 MHz  
CKINn  
f
3
f
4.85–5.67 GHz  
2 kHz–1.475 GHz  
OSC  
f
OUT  
Note: Fmax = 808 MHz for the Si5327, Si5374 and Si5375  
Table 36. Dividers and Limits  
Divider  
Equation  
Si5325, Si5367  
Si5319, Si5324, Si5326, Si5327,  
Si5368, Si5369, Si5374, Si5375  
N1  
N2  
N3  
N1 = N1_HS x NCn_LS  
N2 = N2_HS x N2_LS  
N3 = N3n  
N1_HS = [4, 5, …, 11]  
NCn_LS = [1, 2, 4, 6, …, 2^20]  
N1_HS = [4, 5, …, 11]  
NCn_LS = [1, 2, 4, 6, …, 2^20]  
N2_HS = 1  
N2_LS = [32, 34, 36, …, 2^9]  
N2_HS = [4, 5, …, 11]  
N2_LS = [2, 4, 6, …, 2^20]  
N3n = [1,2,3,..,2^19]  
N3n = [1,2,3,..,2^19]  
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The output divider, NC1, is the product of a high-speed divider (N1_HS) and a low-speed divider (N1_LS).  
Similarly, the feedback divider N2 is the product of a high-speed divider N2_HS and a low-speed divider N2_LS.  
When multiple combinations of high-speed and low-speed divider values are available to produce the desired  
overall result, selecting the largest possible high-speed divider value will produce lower power consumption. With  
the f  
and N1 ranges given above, any output frequency can be achieved from 2 kHz to 945 MHz where NC1  
OSC  
ranges from (4 x 220) to 6. For NC1 = 5, the output frequency range 970 MHz to 1.134 GHz can be obtained. For  
NC1 = 4, the output frequency range from 1.2125 to 1.4175 GHz is available.  
Because there is only one DCO and all of the outputs must be frequencies that are integer divisions of the DCO  
frequency, there are restrictions on the ratio of one output frequency to another output frequency. That is, there is  
considerable freedom in the ratio between the input frequency and the first output frequency; but once the first  
output frequency is chosen, there are restrictions on subsequent output frequencies. These restrictions are caused  
by the fact that the N1_HS divider is shared among all of the outputs. DSPLLsim should be used to determine if two  
different simultaneous outputs are compatible with one another.  
The same issue exists for inputs of different frequency: both inputs, after having been divided by their respective  
N3 dividers, must result in the same f3 frequency because the phase/frequency detector can operate at only one  
frequency at one time.  
7.1.4. Loop Bandwidth (Si5319, Si5326, Si5368, Si5375)  
The device functions as a jitter attenuator with digitally programmable loop bandwidth (BW). The loop bandwidth  
settings range from 60 Hz to 8.4 kHz and are set using the BWSEL_REG[3:0] register bits. The device operating  
frequency should be determined prior to loop bandwidth configuration because the loop bandwidth is a function of  
the phase detector input frequency and the PLL feedback divider. See DSPLLsim for a table of BWSEL_REG and  
associated loop bandwidth settings. For more information the loop BW and its effect on jitter attenuation, see  
7.1.4.1. Low Loop Bandwidth (Si5324, Si5327, Si5369, Si5374)  
The loop BW of the Si5324, Si5327, Si5369, and Si5374 is significantly lower than the BW of the Si5326. The  
available Si5324/27/69/74 loop bandwidth settings and their register control values for a given frequency plan are  
listed by DSPLLsim (Revision 4.0.1 or higher) or in Si537xDSPLLsim. Compared to the Si5326, the BW Si5324/27/  
69/74 settings are approximately 16 times lower, which means that the Si5324/27/69/74 loop bandwidth ranges  
from about 4 to 525 Hz.  
7.1.5. Lock Detect (Si5319, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
The device has a PLL lock detection algorithm that indicates the lock status on the LOL output pin and the  
LOL_INT read-only register bit. See Section “7.11.8. LOL (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369,  
Si5374, Si5375)” for a detailed description of the LOL algorithm.  
7.2. PLL Self-Calibration  
The device performs an internal self-calibration before operation to optimize loop parameters and jitter  
performance. While the self-calibration is being performed, the DCO is being internally controlled by the self-  
calibration state machine, and the LOL alarm will be active. The output clocks can either be active or disabled  
depending on the SQ_ICAL bit setting. The self-calibration time t  
LOCKMP  
All Devices”. The procedure for initiating the internal self-calibration is described below.  
7.2.1. Initiating Internal Self-Calibration  
Any of the following events will trigger an automatic self-calibration:  
Internal DCO registers out-of-range, indicating the need to relock the DCO  
Setting the ICAL register bit to 1  
In any of the above cases, an internal self-calibration will be initiated if a valid input clock exists (no input alarm)  
and is selected as the active clock at that time. The external crystal or reference clock must also be present for the  
self-calibration to begin (LOSX_INT = 0 [narrowband only]).  
When self-calibration is initiated the device generates an output clock if the SQ_ICAL bit is set to 0. The output  
clock will appear when the device begins self-calibration. The frequency of the output clocks may be as high as 5%  
above or as low as 20% below the final locked value. If SQ_ICAL = 1, the output clocks are disabled during self-  
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calibration and will appear after the self-calibration routine is completed. The SQ_ICAL bit is self-clearing after a  
successful ICAL.  
After a successful self-calibration has been performed with a valid input clock, it is not necessary to reinitiate a self-  
calibration for subsequent losses of input clock. If the input clock is lost following self-calibration, the device enters  
digital hold mode. When the input clock returns, the device relocks to the input clock without performing a self-  
calibration.  
After power-up and writing of dividers or PLL registers, the user must set ICAL = 1 to initiate a self-calibration. LOL  
will go low when self calibration is complete. Depending on the selected value of the loop bandwidth, it may take a  
few seconds more for the output frequency and phase to completely settle.  
It is recommended that a software reset precede all ICALs and their associated register writes by setting  
RST_REG (Register 136.7).  
7.2.1.1. PLL Self-Calibration (Si5324, Si5327, Si5369, Si5374)  
Due to the low loop bandwidth of the Si5324, Si5327, Si5369, and Si5374, the lock time of the Si5324/27/69/75 is  
significantly longer than the lock time of the Si5326. As a method of reducing the lock time, the FAST_LOCK  
register bit can be set to improve lock times. As the Si5324/27/69/74 data sheets indicate, FAST_LOCK is the LSB  
of register 137. When FAST_LOCK is high, the lock time decreases. Because the Si5324/27/74 is initialized with  
FAST_LOCK low, it must be written before ICAL is set. Typical Si5324/27/69/74 lock times (as defined from the  
start of ICAL until LOL going low) with FAST_LOCK set are one to two seconds. To further reduce lock times, it is  
also recommended that a value of 001 be written to LOCKT (the three LSBs of register 19).  
7.2.2. Input Clock Stability during Internal Self-Calibration  
An ICAL must occur when the selected active CKINn clock is stable in frequency and with a frequency value that is  
within the operating range that is reported by DSPLLsim. The other CKINs must be stable in frequency (< 100 ppm  
from nominal) or squelched during an ICAL.  
7.2.3. Self-Calibration Caused by Changes in Input Frequency  
If the selected CKINn varies by 500 ppm or more in frequency since the last calibration, the device may initiate a  
self-calibration.  
7.2.4. Narrowband Input-to-Output Skew (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
The input-to-output skew is not controlled. External circuitry is required to control the input-to-output skew. Contact  
Silicon Labs for further information.  
7.2.5. Clock Output Behavior Before and During ICAL  
Table 37. CKOUT_ALWAYS_ON and SQ_ICAL Truth Table  
Cases  
CKOUT_ALWAYS_ON  
SQ_ICAL  
Results  
1
0
0
CKOUT OFF until after the first ICAL  
CKOUT OFF until after the first successful  
ICAL (i.e., when LOL is low)  
2
0
1
1
0
3
CKOUT always ON, including during an ICAL  
CKOUT always ON, including during an ICAL.  
Use these settings to preserve output-to-output  
skew  
4
1
1
Notes:  
1. Case 1 should be selected when an output clock is not desired until the part has been initialized after power-up, but is  
desired all of the time after initialization.  
2. Case 2 should be selected when an output clock is never desired during an any ICAL. Case 2 will only generate  
outputs when the outputs are at the correct output frequency.  
3. Case 3 should be selected whenever a clock output is always desired.  
4. Case 4 is the same as Case 3.  
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7.3. Input Clock Configurations (Si5367 and Si5368)  
The device supports two input clock configurations based on CK_CONFIG_REG. See "6.5. Frame Synchronization  
(Si5366)" on page 70 for additional details.  
7.4. Input Clock Control  
This section describes the clock selection capabilities (manual input selection, automatic input selection, hitless  
switching, and revertive switching). The Si5319, Si5327, and Si5375 support only pin-controlled manual clock  
selection. Figure 27 and Figure 28 provide top level overviews of the clock selection logic, though they do not  
cover wideband or frame sync applications. Register values are indicated by underscored italics. Note that, when  
switching between two clocks, LOL may temporarily go high if the clocks differ in frequency by more than 100 ppm.  
CKIN1  
Selected  
Clock  
CKIN2  
LOS/FOS  
detect  
LOS/FOS  
detect  
4
CK_PRIORn  
Clock priority logic  
CS_CA pin  
1
0
CKSEL_REG  
Auto  
2
AUTOSEL_REG  
decode  
0
1
Manual  
CK_ACTV_PIN  
CKSEL_PIN  
Figure 27. Si5324, Si5325, Si5326, Si5327, and Si5374 Input Clock Selection  
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CKIN1  
CKIN2  
CKIN3  
CKIN4  
Selected  
Clock  
LOS/FOS  
detect  
LOS/FOS  
detect  
LOS/FOS  
detect  
LOS/FOS  
detect  
8
CK_PRIORn  
Clock priority logic  
2
2
CS0_C3A,  
CS1_C4A  
pins  
1
2
2
CKSEL_REG  
0
Auto  
2
AUTOSEL_REG  
decode  
0
1
2
Manual  
CKSEL_PIN  
Figure 28. Si5367, Si5368, and Si5369 Input Clock Selection  
7.4.1. Manual Clock Selection (Si5324, Si5325, Si5326, Si5367, Si5368, Si5369, Si5374)  
Manual control of input clock selection is available by setting the AUTOSEL_REG[1:0] register bits to 00. In manual  
mode, the active input clock is chosen via the CKSEL_REG[1:0] register setting according to Table 38 and  
Table 38. Manual Input Clock Selection (Si5367, Si5368, Si5369)  
CKSEL_REG[1:0]  
Active Input Clock  
CK_CONFIG_REG = 1  
Register Bits  
CK_CONFIG_REG = 0  
(CKIN1,2,3,4 inputs)  
(CKIN1,3 & CKIN2,4 clock/FSYNC pairs)  
00  
01  
10  
11  
CKIN1  
CKIN2  
CKIN3  
CKIN4  
CKIN1/CKIN3  
CKIN2/CKIN4  
Not used  
Not used  
Note: Setting the CKSEL_PIN register bit to one allows the CS [1:0] pins to continue to control input clock selection.  
If CS_PIN is set to zero, the CKSEL_REG[1:0] register bits perform the input clock selection function.  
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Table 39. Manual Input Clock Selection (Si5324, Si5325, Si5326, Si5374)  
CKSEL_REG or CS pin  
Active Input Clock  
CKIN1  
0
1
CKIN2  
If the selected clock enters an alarm condition, the PLL enters digital hold mode. The CKSEL_REG[1:0] controls  
are ignored if automatic clock selection is enabled.  
7.4.2. Automatic Clock Selection (Si5324, Si5325, Si5326, Si5367, Si5368, Si5369, Si5374)  
The AUTOSEL_REG[1:0] register bits sets the input clock selection mode as shown in Table 40. Automatic  
switching is either revertive or non-revertive.  
Table 40. Automatic/Manual Clock Selection  
AUTOSEL_REG[1:0]  
Clock Selection Mode  
Manual  
00  
01  
10  
11  
Automatic Non-revertive  
Automatic Revertive  
Reserved  
CKSEL_PIN is of significance only when Manual is selected.  
7.4.2.1. Detailed Automatic Clock Selection Description (Si5324, Si5325, Si5326, Si5374)  
Automatic switching is either revertive or non-revertive. The default prioritization of clock inputs when the device is  
configured for automatic switching operation is CKIN1, followed by CKIN2, and finally, digital hold mode. The  
inverse input clock priority arrangement is available through the CK_PRIOR bits, as shown in the Si5325, Si5326,  
and Si5374.  
For the default priority arrangement, automatic switching mode selects CKIN1 at powerup, reset, or when in  
revertive mode with no alarms present on CKIN1. If an alarm condition occurs on CKIN1 and there are no active  
alarms on CKIN2, then the device switches to CKIN2. If both CKIN1 and CKIN2 are alarmed, then the device  
enters digital hold mode. If automatic mode is selected and the frequency offset alarms (FOS1_INT and  
FOS2_INT) are disabled, automatic switching is not initiated in response to FOS alarms. The loss-of-signal alarms  
(LOS1_INT and LOS2_INT) are always used in making automatic clock selection choices.  
In non-revertive mode, once CKIN2 is selected, CKIN2 selection remains as long as it is valid even if alarms are  
cleared on CKIN1.  
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7.4.2.2. Detailed Automatic Clock Selection Description (Si5367, Si5368, Si5369)  
The prioritization of clock inputs for automatic switching is shown in Table 41. For example, if  
CK_CONFIG_REG = 0 and the desired clock priority order is CKIN4, CKIN3, CKIN2, and then CKIN1 as the  
lowest priority clock, the user should set CK_PRIOR1[1:0] = 11, CK_PRIOR2[1:0] = 10, CK_PRIOR3[1:0] = 01, and  
CK_PRIOR4[1:0] = 00.  
Table 41. Input Clock Priority for Auto Switching  
Selected Clock  
CK_PRIORn[1:0]  
CK_CONFIG_REG = 0  
CK_CONFIG_REG = 1  
CKIN1/CKIN3  
CKIN2/CKIN4  
Not Used  
00  
01  
10  
11  
CKIN1  
CKIN2  
CKIN3  
CKIN4  
Not Used  
If CK_CONFIG_REG = 1 and the desired clock priority is CKIN1/CKIN3 and then CKIN2/CKIN4, the user should  
set CK_PRIOR1[1:0] = 00 and CK_PRIOR2[1:0] = 01 (CK_PRIOR3[1:0] and CK_PRIOR4[1:0] are ignored in this  
case).  
The following discussion describes the clock selection algorithm for the case of four possible input clocks  
(CK_CONFIG_REG = 0) in the default priority arrangement (priority order CKIN1, CKIN2, CKIN3, CKIN4).  
Automatic switching mode selects CKIN1 at powerup, reset, or when in revertive mode with no alarms present on  
CKIN1. If an alarm condition occurs on CKIN1 and there are no active alarms on CKIN2, the device switches to  
CKIN2. If both CKIN1 and CKIN2 are alarmed and there is no alarm on CKIN3, the device switches to CKIN3. If  
CKIN1, CKIN2, and CKIN3 are alarmed and there is no alarm on CKIN4, the device switches to CKIN4. If alarms  
exist on CKIN1, CKIN2, CKIN3, and CKIN4, the device enters digital hold mode. If automatic mode is selected and  
the frequency offset alarms (FOS1_INT, FOS2_INT, FOS3_INT, FOS4_INT) are disabled, automatic switching is  
not initiated in response to FOS alarms. The loss-of-signal alarms (LOS1_INT, LOS2_INT, LOS3_INT, LOS4_INT)  
are always used in making automatic clock selection choices. In non-revertive mode, once CKIN2 is selected,  
CKIN2 selection remains as long as it is valid even if alarms are cleared on CKIN1.  
7.4.3. Hitless Switching with Phase Build-Out (Si5324, Si5326, Si5327, Si5368, Si5369, Si5374)  
Silicon Laboratories switching technology performs phase build-out, which maintains the phase of the output when  
the input clock is switched. This minimizes the propagation of phase transients to the clock outputs during input  
clock switching. All switching between input clocks occurs within the input multiplexer and phase detector circuitry.  
The phase detector circuitry continually monitors the phase difference between each input clock and the DSPLL  
output clock, f  
. The phase detector circuitry can lock to a clock signal at a specified phase offset relative to f  
OSC  
OSC  
so that the phase offset is maintained by the PLL circuitry.  
At the time a clock switch occurs, the phase detector circuitry knows both the input-to-output phase relationship for  
the original input clock and for the new input clock. The phase detector circuitry locks to the new input clock at the  
new clock's phase offset so that the phase of the output clock is not disturbed. The phase difference between the  
two input clocks is absorbed in the phase detector's offset value, rather than being propagated to the clock output.  
The switching technology virtually eliminates the output clock phase transients traditionally associated with clock  
rearrangement (input clock switching).  
Note that hitless switching between input clocks applies only when the input clock validation time is  
VALTIME[1:0] = 01 or higher.  
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7.5. Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374 and Si5375 Free Run Mode  
Si5319,  
Si5324,  
Si5326,  
Si5327,  
Si5368,  
Si5369,  
Si5374,  
Si5375  
Crystal or an external oscillator  
(external oscillator only for the Si5374/75)  
XB  
XA  
Xtal osc  
XA-XB  
CKIN1  
N31  
CKOUT1  
DSPLL  
Core  
N32  
CKOUT2  
CKIN2  
Control  
I2C/SPI  
Figure 29. Free Run Mode Block Diagram  
CKIN2 has an extra mux with a path to the crystal oscillator output.  
When in Free Run mode, CKIN2 is sacrificed (Si5326, Si5368, Si5369, Si5374).  
Switching between the crystal oscillator and CLKIN1 is hitless.  
Either a crystal or an external oscillator can be used.  
External oscillator connection can be either single ended or differential.  
All other features and specifications remain the same.  
7.5.1. Free Run Mode Programming Procedure  
Using DSPLLsim, determine the frequency plan:  
Write to the internal dividers, including N31 and N32.  
Enable Free Run Mode (the mux select line), FREE_RUN.  
Select CKIN1 as the higher priority clock.  
Establish revertive and autoselect modes.  
Once properly programmed, the part will:  
Initially lock to either the XA/XB (OSC_P and OSC_N for the Si5374/75) or to CKIN1.  
Automatically select CKIN1, if it is available.  
Automatically and hitlessly switch to XA/XB if CKIN1 fails.  
Automatically and hitlessly switch back to CKIN1 when it subsequently returns.  
For the Si5319:  
Clock selection is manual using an input pin.  
Clock switching is not hitless.  
CKIN2 is not available.  
7.5.2. Clock Control Logic in Free Run Mode  
Noting that the mux that selects CKIN2 versus the XA/XB oscillator is located before the clock selection and control  
logic, when in Free Run mode operation, all such logic will be driven by the XA/XB oscillator, not the CKIN2 pins.  
For example, when in Free Run mode, the CK2B pin will reflect the status of the XA/XB oscillator and not the status  
of the CKIN2 pins.  
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7.5.3. Free Run Reference Frequency Constraints  
XA/XB Frequency Min  
109 MHz  
XA/XB Frequency Max  
Xtal  
125.5 MHz  
41 MHz  
3rd overtone  
Fundamental  
37 MHz  
CKIN  
N31  
XA-XB  
N32  
--------------  
-----------------  
= f3  
=
CKOUT  
XA-XB  
---------------------  
Integer  
All crystals and external oscillators must lie within these two bands  
Not every crystal will work; they should be tested  
An external oscillator can be used at all four bands  
The frequency at the phase detector (f3) must be the same for both CKIN1 and XA/XB or else switching cannot  
be hitless  
To avoid spurs, avoid outputs that are an integer (or near integer) of the XA/XB frequency.  
7.5.4. Free Run Reference Frequency Constraints  
While in Free Run:  
CKOUT frequency tracks the reference frequency.  
 For very low drift, a TCXO or OCXO reference is necessary.  
CKOUT Jitter:  
XA/XB to CKOUT jitter transfer function is roughly one-to-one.  
For very low jitter, either use a high quality crystal or external oscillator.  
 3rd overtone crystals have lower close-in phase noise.  
In general, higher XA/XB frequency > lower jitter.  
XA/XB frequency accuracy:  
For hitless switching, to meet all published specifications, the XA/XB frequency divided by N32 should match the CLKIN  
frequency divided by N31. If they do not match, the clock switch will still be well-behaved.  
Other than the above, the absolute accuracy of the XA/XB frequency is not important.  
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7.6. Digital Hold  
All Any-Frequency Precision Clock devices feature a holdover mode, whereby the DSPLL is locked to a digital  
value.  
7.6.1. Narrowband Digital Hold (Si5316, Si5324, Si5326, Si5368, Si5369, Si5374)  
After the part's initial self-calibration (ICAL), when no valid input clock is available, the device enters digital hold.  
Referring to the logical diagram in "Appendix D—Alarm Structure" on page 144, lack of clock availability is defined  
by following the boolean equation for the Si5324, Si5326, and Si5374:  
(LOS1_INT OR FOS1_INT) AND (LOS2_INT OR FOS2_INT) = enter digital hold  
The equivalent Boolean equation for the Si5327 is as follows:  
LOS1 and LOS2 = enter digital hold  
The equivalent boolean equation for the Si5367, Si5368, and Si5369 is as follows:  
(LOS1_INT OR FOS1_INT) AND (LOS2_INT OR FOS2_INT) AND  
(LOS3_INT OR FOS3_INT) AND (LOS4_INT OR FOS4_INT) = enter digital hold  
7.6.1.1. Digital Hold Detailed Description (Si5324, Si5326, Si5327, Si5368, Si5369, Si5374)  
In this mode, the device provides a stable output frequency until the input clock returns and is validated. Upon  
entering digital hold, the internal DCO is initially held to its last frequency value, M (See Figure 30). Next, the DCO  
slowly transitions to a historical average frequency value supplied to the DSPLL, M  
, as shown in Figure 30.  
HIST  
Values of M starting from time t = –(HIST_DEL + HIST_AVG) and ending at t = –HIST_DEL are averaged to  
compute M . This historical average frequency value is taken from an internal memory location that keeps a  
HIST  
record of previous M values supplied to the DCO. By using a historical average frequency, input clock phase and  
frequency transients that may occur immediately preceding digital hold do not affect the digital hold frequency.  
Also, noise related to input clock jitter or internal PLL jitter is minimized.  
Digital Hold  
@
t = 0  
t = –HIST_DEL  
HIST_AVG  
MHIST  
Time  
M
Figure 30. Parameters in History Value of M  
The history delay can be set via the HIST_DEL[4:0] register bits as shown in Table 42 and the history averaging  
time can be set via the HIST_AVG[4:0] register bits as shown in Table 43. The DIGHOLDVALID register can be  
used to determine if the information in HIST_AVG is valid and the device can enter SONET/SDH compliant digital  
hold. If DIGHOLDVALID is not active, the part will enter VCO freeze instead of digital hold.  
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Table 42. Digital Hold History Delay  
HIST_DEL[4:0]  
00000  
00001  
00010  
00011  
00100  
00101  
00110  
00111  
History Delay Time (ms)  
HIST_DEL[4:0]  
10000  
History Delay Time (ms)  
0.0001  
0.0002  
0.0004  
0.0008  
0.0016  
0.0032  
0.0064  
0.01  
6.55  
13  
10001  
10010 (default)  
10011  
26  
52  
10100  
105  
10101  
210  
10110  
419  
10111  
839  
01000  
01001  
01010  
01011  
01100  
01101  
01110  
0.03  
11000  
1678  
3355  
6711  
13422  
26844  
53687  
107374  
214748  
0.05  
11001  
0.10  
11010  
0.20  
11011  
0.41  
11100  
0.82  
11101  
1.64  
11110  
01111  
3.28  
11111  
Table 43. Digital Hold History Averaging Time  
HIST_AVG[4:0] History Averaging Time (ms)  
HIST_AVG[4:0] History Averaging Time (ms)  
00000  
00001  
00010  
00011  
00100  
00101  
00110  
00111  
01000  
01001  
01010  
01011  
01100  
01101  
01110  
01111  
0.0000  
0.0004  
0.001  
0.003  
0.006  
0.012  
0.03  
10000  
10001  
26  
52  
10010  
105  
10011  
210  
10100  
419  
10101  
839  
10110  
1678  
3355  
6711  
0.05  
10111  
0.10  
11000 (default)  
11001  
0.20  
13422  
26844  
53687  
107374  
214748  
429497  
858993  
0.41  
11010  
0.82  
11011  
1.64  
11100  
3.28  
11101  
6.55  
11110  
13  
11111  
If a highly stable reference, such as an oven-controlled crystal oscillator (OCXO) is supplied at XA/XB, an  
extremely stable digital hold can be achieved. If a crystal is supplied at the XA/XB port, the digital hold stability will  
be limited by the stability of the crystal.  
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7.6.2. History Settings for Low Bandwidth Devices (Si5324, Si5327, Si5369, Si5374)  
Because of the extraordinarily low loop bandwidth of the Si5324, Si5369 and Si5374, it is recommended that the  
values for both history registers be increased for longer histories.  
7.6.3. Recovery from Digital Hold (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374)  
When the input clock signal returns, the device transitions from digital hold to the selected input clock. The device  
performs hitless recovery from digital hold. The clock transition from digital hold to the returned input clock includes  
“phase buildout” to absorb the phase difference between the digital hold clock phase and the input clock phase.  
7.6.4. VCO Freeze (Si5319, Si5325, Si5367, Si5375)  
If an LOS or FOS condition exists on the selected input clock, the device enters VCO freeze. In this mode, the  
device provides a stable output frequency until the input clock returns and is validated. When the device enters  
digital hold, the internal oscillator is initially held to the frequency value at roughly one second prior to the leading  
edge of the alarm condition. VCO freeze is not compliant with SONET/SDH MTIE requirements; applications  
requiring SONET/SDH MTIE requirements should use the Si5324, Si5326, Si5368, Si5369 or Si5374. Unlike the  
Si5325 and Si5367, the Si5319’s VCO freeze is controlled by the XA/XB reference (which is typically a crystal)  
resulting in greater stability. For the Si5319, Si5327, and Si5375, VCO freeze is similar to the Digital Hold function  
of the Si5326, Si5368, and Si5369 except that the HIST_AVG and HIST_DEL registers do not exist.  
7.6.5. Digital Hold versus VCO Freeze  
Figure 31 below is an illustration of the difference in behavior between Digital Hold and VCO Freeze.  
Digital Hold  
freq  
HIST_AVG  
HIST_DEL  
f0  
Normal operation  
VCO freeze  
~1 sec  
Input clock drifts  
time  
Clock input  
cable is pulled  
LOS alarm occurs,  
Start Digital hold  
Figure 31. Digital Hold vs. VCO Freeze Example  
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7.7. Output Phase Adjust (Si5326, Si5368)  
The device has a highly accurate, digitally controlled device skew capability. For more information on Output Phase  
Adjustments, see both DSPLLsim and the respective data sheets. Both can be downloaded by going to  
www.silabs.com/timing and clicking on “Documentation” at the bottom of the page.  
7.7.1. Coarse Skew Control (Si5326, Si5368)  
With the INCDEC_PIN register bit set to 0 (pin control off), overall device skew is controlled via the CLAT[7:0]  
register bits. This skew control has a resolution of 1/f  
, approximately 200 ps, and a range from –25.6 to  
OSC  
25.4 ns. Following a powerup or reset (RST pin or RST_REG register bit), the skew will revert to the reset value.  
Any further changes made in the skew register will be read and compared to the previously held value. The  
difference will be calculated and applied to the clock outputs. All skew changes are made in a glitch-free fashion.  
When a phase adjustment is in progress, any new CLAT[7:0] values are ignored until the update is complete. The  
CLATPROG register bit is set to 1 during a coarse skew adjustment. The time for an adjustment to complete is  
dependent on bandwidth and the delta value in CLAT. To verify a written value into CLAT, the CLAT register should  
be read after the register is written. The time that it takes for the effects of a CLAT change to complete is  
proportional to the size of the change, at 83 msec for every unit change, assuming the lowest available loop  
bandwidth was selected. For example, if CLAT is zero and has the value 100 written to it, the changes will  
complete in  
100 x 83 msec = 8.3 sec.  
If it is necessary to set the high-speed output clock divider N1_HS to divide-by-4 in order to achieve the desired  
overall multiplication ratio and output frequency, only phase increments are allowed and negative settings in the  
CLAT register or attempts to decrement the phase via writes to the CLAT register will be ignored. Because of this  
restriction, when there is a choice between using N1_HS = 4 and another N1_HS value that can produce the  
desired multiplication ratio, the other N1_HS value should be selected. This restriction also applies when using the  
INC pin.  
With the INCDEC_PIN register bit set to 1 (pin control on), the INC and DEC pins function the same as they do for  
7.7.1.1. Unlimited Coarse Skew Adjustment (Si5326, Si5368)  
Using the following procedure, the CLAT register can be used to adjust the device clock output phase to an  
arbitrarily large value that is not limited by the size of the CLAT register:  
1. Write a phase adjustment value to the CLAT register (Register 16). The DSPLLsim configuration software  
provides the size of a single step.  
2. Wait until CLATPROGRESS = 0 (register 130, bit 7), which indicates that the adjustment is complete (Maximum  
time for adjustment: 20 seconds for the Si5326 or Si5368).  
3. Set INCDEC_PIN = 1 (Register 21, bit 7).  
4. Write 0 to CLAT register (Register 16).  
5. Wait until CLATPROGRESS = 0.  
6. Set INCDEC_PIN = 0.  
7. Repeat the above process as many times as desired.  
Steps 3-6 will clear the CLAT register without changing the output phase. This allows for unlimited output clock  
phase adjustment using the CLAT register and repeating steps 1–3 as many times as needed.  
Note: The INC and DEC pins must stay low during this process.  
7.7.2. Fine Skew Control (Si5326, Si5368)  
An additional fine adjustment of the overall device skew can be used in conjunction with the INC and DEC pins or  
the CLAT[7:0] register bits to provide finer resolution output phase adjustments. Fine phase adjustment is available  
using the FLAT[14:0] bits. The nominal range and resolution of the FLAT[14:0] skew adjustment word are:  
Range FLAT = ±110 ps  
Resolution FLAT = 9 ps  
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Before writing a new FLAT[14:0] value, the FLAT_VALID bit must be set to 0 to hold the existing FLAT[14:0] value  
while the new value is being written. Once the new value is written, set FLAT_VALID = 1 to enable its use.  
To verify a written value into FLAT, the FLAT register should be read after the register is written.  
Because the FLAT resolution varies with the frequency plan and selected bandwidth, DSPLLsim reports the FLAT  
resolution each time it creates a new frequency plan.  
7.7.2.1. Output Phase Adjust (Si5324, Si5327, Si5369, Si5374)  
Because of its very low loop bandwidth, the output phase of the Si5324, Si5327, Si5369, and Si5374 are not  
adjustable. This means that the Si5324, Si5327, Si5369, and Si5374 do not have any INC or DEC pins and that  
they do not have CLAT or FLAT registers.  
7.7.3. Independent Skew (Si5324, Si5326, Si5368, Si5369, Si5374)  
The phase of each clock output may be adjusted in relation to the phase of the other clock outputs, respectively.  
This feature is available when CK_CONFIG_REG = 0. The resolution of the phase adjustment is equal to [NI HS/  
F
]. Since F  
is approximately 5 GHz and N1_HS = (4, 5, 6, …, 11), the resolution varies from approximately  
VCO  
VCO  
800 ps to 2.2 ns depending on the PLL divider settings. Silicon Laboratories' PC-based configuration software  
(DSPLLsim) provides PLL divider settings for each frequency translation, if applicable. If more than one set of PLL  
divider settings is available, selecting the combination with the lowest N1_HS value provides the finest resolution  
for output clock phase offset control. The INDEPENDENTSKEWn[7:0] (n = 1 to 5) register bits control the phase of  
the device output clocks. By programming a different phase offset for each output clock, output-to-output delays  
can easily be set.  
7.7.4. Output-to-output Skew (Si5324, Si5326, Si5327, Si5368, Si5369, Si5374)  
The output-to-output skew is guaranteed to be preserved only if the following two register bits are both high:  
Register Bit:  
Location  
CKOUT_ALWAYS_ON  
SQICAL  
addr 0, bit 5  
addr 3, bit 4  
In addition, if SFOUT is changed, the output-to-output skew may be disturbed until after a successful ICAL.  
Note: CKOUT5 phase is random unless it is used for Frame Sync (See section 7.8).  
7.7.5. Input-to-Output Skew (All Devices)  
The input-to-output skew for these devices is not controlled.  
7.8. Frame Synchronization Realignment (Si5368 and CK_CONFIG_REG = 1)  
Frame Synchronization Realignment is selected by setting CK_CONFIG_REG = 1. In a typical frame  
synchronization application, CKIN1 and CKIN2 are high-speed input clocks from primary and secondary clock  
generation cards and CKIN3 and CKIN4 are their associated primary and secondary frame synchronization  
signals. The device generates four output clocks and a frame sync output FS_OUT. CKIN3 and CKIN4 control the  
phase of FS_OUT. When CK_CONFIG_REG = 1, the Si5368 can lock onto only CKIN1 or CKIN2. CKIN3 and  
CKIN4 are used only for purposes of frame synchronization.  
The inputs supplied to CKIN3 and CKIN4 can range from 2 to 512 kHz. So that two different frame sync input  
frequencies can be accommodated, CKIN3 and CKIN4 each have their own input dividers, as shown in Figure 32.  
The CKIN3 and CKIN4 frequencies are set by the CKIN3RATE[2:0] and CKIN4RATE[2:0] register bits, as shown in  
Table 44. The frequency of FS_OUT can range from 2 kHz to 710 MHz and is set using the NC5_LS divider  
setting. FS_OUT must divide evenly into CKOUT2. For example, if CKOUT2 is 156.25 MHz, then 8 kHz would not  
be an acceptable frame rate because 156.25 MHz/8 kHz = 19,531.25, which is not an integer. However, 2 kHz  
would be an acceptable frame rate because 156.25 MHz/2 kHz = 78,125.  
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Table 44. CKIN3/CKIN4 Frequency Selection (CK_CONF = 1)  
CKLNnRATE[2:0]  
CKINn Frequency (kHz)  
Divisor  
000  
001  
010  
011  
100  
101  
110  
111  
2–4  
4–8  
1
2
8–16  
4
16–32  
32–64  
64–128  
128–256  
256–512  
8
16  
32  
64  
128  
DCO,  
4.85 GHz  
to 5.67 GHz  
N1_HS  
CKOUT2  
FS_OUT  
NC2_LS  
NC5_LS  
CKIN3  
CKIN4  
CLKIN3RATE  
CLKIN4RATE  
to align  
Clock select  
Typically the same frequency  
Figure 32. Frame Sync Frequencies  
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The NC5_LS divider uses CKOUT2 as its clock input to derive FS_OUT. The limits for the NC5_LS divider are  
19  
NC5_LS = [1, 2, 4, 6, …, 2 ]  
f
< 710 MHz  
CKOUT2  
Note that when in frame synchronization realignment mode, writes to NC5_LS are controlled by FPW_VALID. See  
Common NC5_LS divider settings on FS_OUT are shown in Table 45.  
Table 45. Common NC5 Divider Settings  
CKOUT2 Frequency (MHz)  
NC5 Divider Setting  
2 kHz FS_OUT 8 kHz FS_OUT  
19.44  
77.76  
9720  
38880  
77760  
311040  
2430  
9720  
155.52  
622.08  
19440  
77760  
7.8.1. FSYNC Realignment (Si5368)  
The FSYNC_ALIGN_PIN bit determines if the realignment will be pin-controlled via the FS_ALIGN pin or register-  
controlled via the FSYNC_ALIGN_REG register bit. The active CKIN3 or CKIN4 edge to be used is controlled via  
the FSYNC_POL register bit.  
In either FSYNC alignment control mode, the resolution of the phase realignment is 1 clock cycle of CKOUT2. If  
the realignment control is not active, the NC5 divider will continuously divide down its f  
input. This  
CKOUT2  
guarantees a fixed number of high-frequency clock (CKOUT2) cycles between each FS_OUT cycle.  
At power-up, the device automatically performs a realignment of FS_OUT using the currently active sync input.  
After this, as long as the PLL remains in lock and a realignment is not requested, FS_OUT will include a fixed  
number of high-speed clock cycles, even if input clock switches are performed. If many clock switches are  
performed in phase build-out mode, it is possible that the input sync to output sync phase relationship will shift due  
to the accumulated residual phase transients of the phase build-out circuitry. The ALIGN_ERR[8:0] status register  
reports the deviation of the input-to-output sync phase skew from the desired FSYNC_SKEW[16:0] value in units of  
f
periods. A programmable threshold to trigger the ALIGN_INT alarm can be set via the ALIGN_THR[2:0]  
CKOUT2  
bits, whose settings are given in Table 46. If the sync alignment error exceeds the threshold in either the positive or  
negative direction, the alarm becomes active. If it is then desired to reestablish the desired input-to-output sync  
phase relationship, a realignment can be performed. A realignment request may cause FS_OUT to  
instantaneously shift its output edge location in order to align with the active input sync phase.  
Table 46. Alignment Alarm Trigger Threshold  
ALIGN_THR [2:0]  
Alarm Trigger Threshold (Units of T  
)
CKOUT2  
000  
001  
010  
011  
100  
101  
110  
111  
4
8
16  
32  
48  
64  
96  
128  
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For cases where phase skew is required, see Section “7.7. Output Phase Adjust (Si5326, Si5368)” for more details  
on controlling the sync input to sync output phase skew via the FSYNC_SKEW[16:0] bits. See Section “8.2. Output  
Clock Drivers” for information on the FS_OUT signal format, pulse width, and active logic level control.  
7.8.2. FSYNC Skew Control (Si5368)  
When CKIN3 and CKIN4 are configured as frame sync inputs (CK_CONFIG_REG = 1), phase skew of the sync  
input active edge to FS_OUT active edge is controllable via the FSYNC_SKEW[16:0] register bits. Skew control  
has a resolution of 1/f  
and a range of 131,071/f  
. The entered skew value must be less than the  
CKOUT2  
CKOUT2  
period of CKIN3, CKIN4, and FS_OUT.  
The skew should not be changed more than once per FS_OUT period. If a FSYNC realignment is being made, the  
skew should not be changed until the realignment is complete. The skew value and the FS_OUT pulse width  
should not be changed within the same FS_OUT period.  
Before writing the three bytes needed to specify a new FSYNC_SKEW[16:0] value, the user should set the register  
bit FSKEW_VALID = 0. This causes the alignment state machine to keep using the previous FSYNC_SKEW[16:0]  
value, ignoring the new register values as they are being written. Once the new FSYNC_SKEW[16:0] value has  
been completely written, the user should set FSKEW_VALID = 1 at which time the alignment state machine will  
read the new skew alignment value. Note that when the new FSYNC_SKEW[16:0] value is used, a phase step will  
occur in FS_OUT.  
7.8.3. Including FSYNC Inputs in Clock Selection (Si5368)  
The frame sync inputs, CKIN3 and CKIN4, are both monitored for loss-of-signal (LOS3_INT and LOS4_INT)  
conditions. To include these LOS alarms in the input clock selection algorithm, set FSYNC_SWTCH_REG = 1. The  
LOS3_INT is logically ORed with LOS1_INT and LOS4_INT is ORed with LOS2_INT as inputs to the clock  
selection state machine. If it is desired not to include these alarms in the clock selection algorithm, set  
FSYNC_SWTCH_REG = 0. The frequency offset (FOS) alarms for CKIN1 and CKIN2 can also be included in the  
state machine decision making as described in Section “7.11. Alarms (Si5319, Si5324, Si5325, Si5326, Si5327,  
Si5367, Si5368, Si5369, Si5374, Si5375)”; however, in frame sync mode (CK_CONFIG_REG = 1), the FOS alarms  
for CKIN3 and CKIN4 are ignored.  
7.8.4. FS_OUT Polarity and Pulse Width Control (Si5368)  
Additional output controls are available for FS_OUT. The active polarity of FS_OUT is set via the FS_OUT_POL  
register bit and the active duty cycle is set via the FSYNC_PW[9:0] register. Pulse width settings have a resolution  
of 1/f  
, and a 50% duty cycle setting is provided. Pulse width settings can range from 1 to (NC5-1) CKOUT2  
CKOUT2  
periods, providing the full range of pulse width possibilities for a given NC5 divider setting.  
The FS_OUT pulse should not be changed more than once per FS_OUT period. If a FSYNC realignment is being  
made, the pulse width should not be changed until the realignment is complete. The FS_OUT pulse width and the  
skew value should not be changed within the same FS_OUT period.  
Before writing a new value into FSYNC_PW[9:0], the user should set the register bit FPW_VALID = 0. This causes  
the FS_OUT pulse width state machine to keep using the previous FSYNC_PW[9:0] value, ignoring the new  
register values as they are being written. Once the new FSYNC_PW[9:0] value has been completely written, the  
user should set FPW_VALID = 1, at which time the FS_OUT pulse width state machine will read the new pulse  
width value.  
Writes to NC5_LS should be treated the same as writes to FSYNC_PW. Thus, all writes to NC5_LS should occur  
only when FPW_VALID = 0. Any such writes will not take effect until FPW_VALID = 1.  
Note that f  
must be less than or equal to 710 MHz when CK_CONFIG_REG = 1; otherwise, the FS_OUT  
CKOUT2  
buffer and NC5 divider must be disabled.  
7.8.5. Using FS_OUT as a Fifth Output Clock (Si5368)  
In applications where the frame synchronization functionality is not needed (CK_CONFIG_REG = 0), FS_OUT can  
be used as a fifth clock output. In this case, no realignment requests should be made to the NC5 divider (hold  
FS_ALIGN = 0 and FSYNC_ALIGN_REG = 0). Output pulse width and polarity controls for FS_OUT are still  
available as described above. The 50% duty cycle setting would be used to generate a typical balanced output  
clock.  
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7.9. Output Clock Drivers (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5368,  
Si5369, Si5374, Si5375)  
The device includes a flexible output driver structure that can drive a variety of loads, including LVPECL, LVDS,  
CML, and CMOS formats. The signal format of each output is individually configurable through the  
SFOUTn_REG[2:0] register bits, which modify the output common mode and differential signal swing.  
Table 47 shows the signal formats based on the supply voltage and the type of load being driven. For the CMOS  
setting, both output pins drive single-ended in-phase signals and should be externally shorted together to obtain  
the maximum drive strength.  
Table 47. Output Signal Format Selection  
SFOUTn_REG[2:0]  
Signal Format  
LVDS  
111  
110  
CML  
101  
LVPECL  
011  
Low-swing LVDS  
CMOS  
010  
000  
Disabled  
All Others  
Reserved  
The SFOUTn_REG[2:0] register bits can also be used to disable the outputs. Disabling the outputs puts the  
CKOUT+ and CKOUT– pins in a high-impedance state relative to V (common mode tri-state) while the two  
DD  
outputs remain connected to each other through a 200 on-chip resistance (differential impedance of 200 ). The  
clock output buffers and DSPLL output dividers NCn are powered down in disable mode.  
The additional functions of “Hold Logic 1” and “Hold Logic 0”, which create static logic levels at the outputs, are  
available. For differential output buffer formats, the Hold Logic 1 state causes the positive output of the differential  
signal to remain at its high logic level while the negative output remains at the low logic level. For CMOS output  
buffer format, both outputs remain high during the Hold Logic 1 state. These functions are controlled by the  
HLOG_n bits. When entering or exiting the “Hold Logic 1” or “Hold Logic 0” states, no glitches or runt pulses are  
generated on the outputs. Changes to SFOUT or HLOG will change the output phase. An ICAL is required to re-  
establish the output phase. When SFOUT = 010 for CMOS, bypass mode is not supported.  
7.9.1. Disabling CKOUTn  
Disabling CKOUTn output powers down the output buffer and output divider. Individual disable controls are  
available for each output using the DSBLn_REG.  
7.9.2. LVPECL TQFP Output Signal Format Restrictions at 3.3 V (Si5367, Si5368, Si5369)  
The LVPECL and CMOS output formats draw more current than either LVDS or CML; therefore, there are  
restrictions in the allowed output format pin settings that limit the maximum power dissipation for the TQFP devices  
when they are operated at 3.3 V. When Vdd = 3.3 V and there are four enabled LVPECL or CMOS outputs, the fifth  
output must be disabled. When Vdd = 3.3 V and there are five enabled outputs, there can be no more than three  
outputs that are either LVPECL or CMOS. All other configurations are valid, including all with Vdd = 2.5 V.  
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7.10. PLL Bypass Mode (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5368, Si5369,  
Si5374, Si5375)  
The device supports a PLL bypass mode in which the selected input clock is fed directly to the output buffers,  
bypassing the DSPLL. In PLL bypass mode, the input and output clocks will be at the same frequency. PLL bypass  
mode is useful in a laboratory environment to measure system performance with and without the jitter attenuation  
provided by the DSPLL. The BYPASS_REG bit controls enabling/disabling PLL bypass mode.  
Before going into bypass mode, it is recommended that the part enter Digital Hold by setting DHOLD. Internally, the  
bypass path is implemented with high-speed differential signaling for low jitter. Note that the CMOS output format  
does not support bypass mode.  
7.11. Alarms (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5368, Si5369, Si5374,  
Si5375)  
Summary alarms are available to indicate the overall status of the input signals and frame alignment (Si5368 only).  
Alarm outputs stay high until all the alarm conditions for that alarm output are cleared. The Register VALTIME  
controls how long a valid signal is re-applied before an alarm clears. Table 48 shows the available settings. Note  
that only for VALTIME[1:0] = 00, hitless switching is not possible.  
Table 48. Loss-of-Signal Validation Times  
VALTIME[1:0]  
Clock Validation Time  
00  
2 ms  
(hitless switching not available)  
01  
10  
11  
100 ms  
200 ms  
13 s  
7.11.1. Loss-of-Signal Alarms (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5368, Si5369, Si5374,  
Si5375)  
The device has loss-of-signal circuitry that continuously monitors CKINn for missing pulses. The LOS circuitry  
generates an internal LOSn_INT output signal that is processed with other alarms to generate CnB and  
ALARMOUT.  
An LOS condition on CKIN1 causes the internal LOS1_INT alarm become active. Similarly, an LOS condition on  
CKINn causes the LOSn_INT alarm become active. Once a LOSn_INT alarm is asserted on one of the input  
clocks, it remains asserted until that input clock is validated over a designated time period. If another error  
condition on the same input clock is detected during the validation time then the alarm remains asserted and the  
validation time starts over.  
7.11.1.1. Narrowband LOS Algorithms (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
There are three options for LOS: LOS, LOS_A, and no LOS, which are selected using the LOSn_EN registers. The  
values for the LOSn_EN registers are given in Table 49.  
Table 49. Loss-of-Signal Registers  
LOSn_EN[1:0]  
LOS Selection  
Disable all LOS monitoring  
Reserved  
00  
01  
10  
11  
LOS_A enabled  
LOS enabled  
96  
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7.11.1.2. Standard LOS (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
To facilitate automatic hitless switching, the LOS trigger time can be significantly reduced by using the default LOS  
option (LOSn_EN = 11). The LOS circuitry divides down each input clock to produce a 2 kHz to 2 MHz signal. The  
LOS circuitry over samples this divided down input clock using a 40 MHz clock to search for extended periods of  
time without input clock transitions. If the LOS monitor detects twice the normal number of samples without a clock  
edge, an LOS alarm is declared. The LOSn trigger window is based on the value of the input divider N3. The value  
of N3 is reported by DSPLLsim.  
The range over which LOS is guaranteed to not produce false positive assertions is 100 ppm. For example, if a  
device is locked to an input clock on CKIN1, the frequency of CKIN2 should differ by no more than 100 ppm to  
avoid false LOS2 assertions.  
The frequency range over which FOS monitoring may occur is from 10 to 710 MHz.  
7.11.1.3. LOSA (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
A slower response version of LOS called LOSA is available and should be used under certain conditions. Because  
LOSA is slower and less sensitive than LOS, its use should be considered for applications with quasi-periodic  
clocks (e.g., gapped clocks with one or more consecutive clock edges removed), when switching between input  
clocks with a large difference in frequency and any other application where false positive assertions of LOS may  
incorrectly cause the Any-Frequency device to be forced into Digital Hold.  
For example, it is recommended that while in Free Run Mode LOSA be used instead of LOS because the two clock  
inputs will not be the same exact frequency. This will avoid false LOS assertions when the XA/XB frequency differs  
from the other clock inputs by more than 100 ppm. See Section 7.11.1.3 for more information on LOSA.  
7.11.1.4. LOS disabled (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
For situations where no form of LOS is desired, LOS can be disabled by writing 00 to LOSn_EN. This mode is  
provided to support applications which implement custom LOS algorithms off-chip. If this approach is taken, the  
only remaining methods of entering Digital Hold will be FOS or by setting DHOLD (register 3, bit 5).  
7.11.1.5. Wideband LOS Algorithm (Si5322, Si5365)  
Each input clock is divided down to produce a 78 kHz to 1.2 MHz signal before entering the LOS monitoring  
circuitry. The same LOS algorithm as described in the above section is then used. FOS is not available in wideband  
devices.  
7.11.1.6. LOS Alarm Outputs (Si5319, Si5324, Si5325, Si5326, Si5327, Si5367, Si5369, Si5374, Si5375)  
When LOS is enabled, an LOS condition on CKIN1 causes LOS1_INT to become active. Similarly, when LOS is  
enabled, an LOS condition on CKIN2 causes LOS2_INT to become active. Once a LOSn_INT alarm is asserted on  
one of the input clocks, it remains asserted until the input clock is validated over a designated time period. If  
another error condition on the same input clock is detected during the validation time then the alarm remains  
asserted and the validation time starts over.  
7.11.2. FOS Algorithm (Si5324, Si5325, Si5326, Si5368, Si5369, Si5374)  
The frequency offset (FOS) alarms indicate if the input clocks are within a specified frequency range relative to the  
frequency of a reference clock. The reference clock can be provided by any of the four input clocks (two for Si5324,  
Si5325 or Si5326) or the XA/XB input. The default FOS reference is CKIN2. The frequency monitoring circuitry  
compares the frequency of the input clock(s) with the FOS reference clock If the frequency offset of an input clock  
exceeds a selected frequency offset threshold, an FOS alarm (FOS_INT register bit) is declared for that clock  
input. Be aware that large amounts of wander can cause false FOS alarms.  
Note: For the Si5368, If CK_CONFIG_REG = 1, only CKIN1 and CKIN2 are monitored; CKIN3 and CKIN4 are used for  
FSYNC and are not monitored.  
The frequency offset threshold is selectable using the FOS_THR[1:0] bits. Settings are available for compatibility  
with SONET Minimum Clock (SCMD) or Stratum 3/3E requirements. See Table 8 on page 40. The device supports  
FOS hystereses per GR-1244-CORE, making the device less susceptible to FOS alarm chattering. A reference  
clock with suitable accuracy and drift specifications to support the intended application should be used. The FOS  
reference clock is set via the FOSREFSEL[2:0] bits as shown in Table 50. More than one input can be monitored  
against the FOS reference, i.e., there can be more than one monitored clock, but only one FOS reference. When  
the XA/XB input is used as the FOS reference, there is only one reference frequency band that is allowed: from  
37 MHz to 41 MHz.  
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Table 50. FOS Reference Clock Selection  
FOS Reference  
FOSREFSEL[2:0]  
Si5326  
XA/XB  
Si5368  
XA/XB  
000  
001  
CKIN1  
CKIN1  
010  
CKIN2 (default)  
Reserved  
Reserved  
Reserved  
CKIN2 (default)  
CKIN3  
011  
100  
CKIN4  
all others  
Reserved  
Both the FOS reference and the FOS monitored clock must be divided down to the same clock rate and this clock  
rate must be between 10 MHz and 27 MHz. As can be seen in Figure 33, the values for P and Q must be selected  
so that the FOS comparison occurs at the same frequency. The registers that contain the values for P and Q are  
the CKINnRATE[2:0] registers.  
CKIN  
P
FOS  
Compare  
FOS_REF  
Q
10 MHz min,  
27 MHz max  
Figure 33. FOS Compare  
The frequency band of each input clock must be specified to use the FOS feature. The CLKNRATE registers  
specify the frequency of the device input clocks as shown in Table 51.  
When the FOS reference is the XA/XB oscillator (either internal or external), the value of Q in Figure 33 is always  
2, for an effective CLKINnRATE of 1, as shown in Table 51.  
Table 51. CLKnRATE Registers  
CLKnRATE  
Divisor, P or Q  
Min Frequency, MHz  
Max Frequency, MHz  
0
1
2
3
4
5
1
2
10  
25  
27  
54  
4
50  
105  
215  
435  
710  
8
95  
16  
32  
190  
375  
For example, to monitor a 544 MHz clock at CKIN1 with a FOS reference of 34 MHz at CKIN2:  
CLK1RATE = 5  
CLK2RATE = 1  
FOSREFSEL[2:0] = 010  
98  
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7.11.3. C1B, C2B (Si5319, Si5324, Si5325, Si5326, Si5327, Si5374, Si5375)  
A LOS condition causes the associated LOS1_INT or LOS2_INT read only register bit to be set. A LOS condition  
on CKIN_1 will also be reflected onto C1B if CK1_BAD_PIN = 1. Likewise, a LOS condition on CKIN_2 will also be  
reflected onto C2B if CK2_BAD_PIN = 1.  
A FOS condition causes the associated FOS1_INT or FOS2_INT read only register bit to be set. FOS monitoring is  
enabled or disabled using the FOS_EN bit. If FOS is enabled (FOS_EN = 1) and CK1_BAD_PIN = 1, a FOS  
condition will also be reflected onto its associated output pin, C1B or C2B. If FOS is disabled (FOS_EN = 0), the  
FOS1_INT and FOS2_INT register bits do not affect the C1B and C2B alarm outputs, respectively.  
Once an LOS or FOS alarm is asserted on one of the input clocks, it is held high until the input clock is validated  
over a designated time period. The validation time is programmable via the VALTIME[1:0] register bits as shown in  
Table 48 on page 96. If another error condition on the same input clock is detected during the validation time then  
the alarm remains asserted and the validation time starts over.  
[Si5326]: Note that hitless switching between input clocks applies only when the input clock validation time  
VALTIME[1:0] = 01 or higher.  
7.11.4. LOS (Si5319, Si5375)  
A LOS condition causes the LOS_INT read only register bit to be set. This LOS condition will also be reflected onto  
the INT_CB pin.  
7.11.5. C1B, C2B, C3B, ALRMOUT (Si5367, Si5368, Si5369 [CK_CONFIG_REG = 0])  
The generation of alarms on the C1B, C2B, C3B, and ALRMOUT outputs is a function of the input clock  
configuration, and the frequency offset alarm enable as shown in Table 52. The LOSn_INT and FOSn_INT signals  
are the raw outputs of the alarm monitors. These appear directly in the device status registers. Sticky versions of  
these bits (LOSn_FLG, FOSn_FLG) drive the output interrupt and can be individually masked. When the device  
inputs are configured as four input clocks (CK_CONFIG = 0), the ALRMOUT pin reflects the status of the CKIN4  
input. The equations below assume that the output alarm is active high; however, the active polarity is selectable  
via the CK_BAD_POL bit.  
Operation of the C1B, C2B, C3B, and ALRMOUT pins is enabled based on setting the C1B_PIN, C2B_PIN,  
C3B_PIN, and ALRMOUT_PIN register bits. Otherwise, the pin will tri-state. Also, if INT_PIN = 1, the interrupt  
functionality will override the appearance of ALRMOUT at the output even if ALRMOUT_PIN = 1.  
Once an LOS or FOS alarm is asserted for one of the input clocks, it is held high until the input clock is validated  
over a designated time period. The validation time is programmable via the VALTIME[1:0] register bits as shown in  
Table 48 on page 96. If another error condition on the same input clock is detected during the validation time then  
the alarm remains asserted and the validation time starts over.  
Note that hitless switching between input clocks applies only when the input clock validation time  
VALTIME[1:0] = 01 or higher.  
Table 52. Alarm Output Logic Equations (Si5367, Si5368, and Si5369 [CONFIG_REG = 0])  
FOS_EN  
Alarm Output Equations  
0
C1B = LOS1_INT  
C2B = LOS2_INT  
(Disables FOS)  
C3B = LOS3_INT  
ALRMOUT = LOS4_INT  
1
C1B = LOS1_INT or FOS1_INT  
C2B = LOS2_INT or FOS2_INT  
C3B = LOS3_INT or FOS3_INT  
ALRMOUT = LOS4_INT or FOS4_INT  
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7.11.6. C1B, C2B, C3B, ALRMOUT (Si5368 [CK_CONFIG_REG = 1])  
The generation of alarms on the C1B, C2B, C3B, and ALRMOUT outputs is a function of the input clock  
configuration, and the frequency offset alarm enable as shown in Table 53. The LOSn_INT and FOSn_INT signals  
are the raw outputs of the alarm monitors. These appear directly in the device status registers. Sticky versions of  
these bits (LOSn_FLG, FOSn_FLG) drive the output interrupt and can be individually masked. Since, CKIN3 and  
CKIN4 are configured as frame sync inputs (CK_CONFIG_REG = 1), ALRMOUT functions as the alignment alarm  
output (ALIGN_INT) as described in Section “7.8. Frame Synchronization Realignment (Si5368 and  
CK_CONFIG_REG = 1)”. The equations below assume that the output alarm is active high; however, the active  
polarity is selectable via the CK_BAD_POL bit.  
Operation of the C1B, C2B, C3B, and ALRMOUT pins is enabled based on setting the C1B_PIN, C2B_PIN,  
C3B_PIN, and ALRMOUT_PIN register bits. Otherwise, the pin will tri-state. Also, if INT_PIN = 1, the interrupt  
functionality will override the appearance of ALRMOUT at the output even if ALRMOUT_PIN = 1.  
Once an LOS or FOS alarm is asserted for one of the input clocks, it is held high until the input clock is validated  
over a designated time period. The validation time is programmable via the VALTIME[1:0] register bits as shown in  
Table 8, “AC Characteristics—All Devices”. If another error condition on the same input clock is detected during the  
validation time then the alarm remains asserted and the validation time starts over.  
Note that hitless switching between input clocks applies only when the input clock validation time  
VALTIME[1:0] = 01 or higher.  
Table 53. Alarm Output Logic Equations [Si5368 and CKCONFIG_REG = 1]  
FOS_EN  
Alarm Output Equations  
0
C1B = LOS1_INT or (LOS3_INT and FSYNC_SWTCH_REG)  
C2B = LOS2_INT or (LOS4_INT and FSYNC_SWTCH_REG)  
C3B tri-state,  
(Disables FOS)  
ALRMOUT = ALIGN_INT  
1
C1B = LOS1_INT or (LOS3_INT and FSYNC_SWTCH_REG) or  
FOS1_INT  
C2B = LOS2_INT or (LOS4_INT and FSYNC_SWTCH_REG) or  
FOS2_INT  
C3B tri-state,  
ALRMOUT = ALIGN_INT  
7.11.7. LOS Algorithm for Reference Clock Input (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374,  
Si5375)  
The reference clock input on the XA/XB port is monitored for LOS. The LOS circuitry divides the signal at XA/XB by  
128, producing a 78 kHz to 1.2 MHz signal, and monitors the signal for LOS using the same algorithm as described  
Si5374, Si5375)”. The LOSX_INT read only bit reflects the state of a loss-of-signal monitor on the XA/XB port. For  
the Si5374 and Si5375, the XA/XB port refers to the OSC_P and OSC_N pins.  
7.11.8. LOL (Si5319, Si5324, Si5326, Si5327, Si5368, Si5369, Si5374, Si5375)  
The device has a PLL lock detection algorithm that indicates the lock status on the LOL output pin and the  
LOL_INT read-only register bit. The algorithm works by continuously monitoring the phase of the input clock in  
relation to the phase of the feedback clock. A retriggerable one-shot is set each time a potential phase cycle slip  
condition is detected. If no potential phase cycle slip occurs for the retrigger time, the LOL output is set low,  
indicating the PLL is in lock. The LOL pin is held in the active state during an internal PLL calibration. The active  
polarity of the LOL output pin is set using the LOL_POL register bit (default active high).  
The lock detect retrigger time is user-selectable, independent of the loop bandwidth. The LOCKT[2:0] register bits  
must be set by the user to the desired setting. Table 54 shows the lock detect retrigger time for both modes of  
operation. LOCKT is the minimum amount of time that LOL will be active.  
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Table 54. Lock Detect Retrigger Time (LOCKT)  
LOCKT[2:0]  
000  
Retrigger Time (ms)  
106  
001  
53  
010  
26.5  
011  
13.3  
100  
6.6 (value after reset)  
101  
3.3  
110  
1.66  
.833  
111  
7.11.9. Device Interrupts  
Alarms on internal real-time status bits such as LOS1_INT, FOS1_INT, etc. cause their associated interrupt flags  
(LOS1_FLG, FOS1_FLG, etc.) to be set and held. The interrupt flag bits can be individually masked or unmasked  
with respect to the output interrupt pin. Once an interrupt flag bit is set, it will remain high until the register location  
is written with a “0” to clear the flag.  
7.12. Device Reset  
Upon powerup or asserting Reset via the RST pin or software, the device internally executes a power-on-reset  
(POR) which resets the internal device logic and tristates the device outputs. The device waits for configuration  
commands and the receipt of the ICAL = 1 command to start its calibration. Any changes to the CMODE pin  
require that RST be toggled to reset the part. The power-up default register values are given in the data sheets for  
these parts.  
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2
7.13. I C Serial Microprocessor Interface  
2
When configured in I C control mode (CMODE = L), the control interface to the device is a 2-wire bus for  
bidirectional communication. The bus consists of a bidirectional serial data line (SDA) and a serial clock input  
(SCL). Both lines must be connected to the positive supply via an external pull-up. In addition, an output interrupt  
(INT) is provided with selectable active polarity (determined by INT_POL bit). Fast mode operation is supported for  
2
transfer rates up to 400 kbps as specified in the I C-Bus Specification standard. To provide bus address flexibility,  
three pins (A[2:0]) are available to customize the LSBs of the device address. The complete bus address for the  
device is as follows:  
1 1 0 1 A[2] A[1] A[0] R/W.  
Figure 34 shows the command format for both read and write access. Data is always sent MSB first. The timing  
2
2
specifications and timing diagram for the I C bus can be found in the I C-Bus Specification standard (fast mode  
2
The maximum I C clock speed is 400 kHz.  
Byte  
Address  
S
S
Slave Address  
Slave Address  
0
0
A
A
A
Data  
A
Data  
A
P
Write Command  
Byte  
Address  
A
S
Slave Address  
1
A
Data  
A
Data  
A
P
Read Command  
–address auto incremented after each data read or write  
(this can be two separate transactions)  
A – Acknowledge (SDA LOW)  
From master to slave  
– START condition  
– STOP condition  
S
P
From slave to master  
Figure 34. I2C Command Format  
In Figure 35, the value 68 is seven bits. The sequence of the example is: Write register 00 with the value 0xAA;  
then, read register 00. Note that 0 = Write = W, and 1 = Read = R.  
S
Slave Address  
68  
0
A
Byte Address  
00  
A
Data  
AA  
A
W
Write Command  
S
Slave Address  
68  
0
A
A
S
Slave Address  
68  
1
A
Data  
AA  
Byte Address  
00  
R
W
Read Command  
Figure 35. I2C Example  
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7.14. Serial Microprocessor Interface (SPI)  
When configured in SPI control mode (CMODE = H), the control interface to the device is a 4-wire interface  
modeled after commonly available microcontroller and serial peripheral devices. The interface consists of a clock  
input (SCLK), slave select input (SSb), serial data input (SDI), and serial data output (SDO). In addition, an output  
interrupt (INT) is provided with selectable active polarity (determined by INT_POL bit).  
Data is transferred a byte at a time with each register access consisting of a pair of byte transfers. Figure 36 and  
Figure 37 illustrate read and write/set address operations on the SPI bus, and AC SPEC gives the timing  
requirements for the interface. Table 55 shows the SPI command format.  
Table 55. SPI Command Format  
Instruction(BYTE0)  
00000000—Set Address  
Address/Data[7:0](BYTE1)  
AAAAAAAA  
01000000—Write  
DDDDDDDD  
01100000—Write/Address Increment  
10000000—Read  
DDDDDDDD  
DDDDDDDD  
10100000—Read/Address Increment  
DDDDDDDD  
The first byte of the pair is the instruction byte. The “Set Address” command writes the 8 bit address value that will  
be used for the subsequent read or write. The “Write” command writes data into the device based on the address  
previously established and the “Write/Address Increment” command writes data into the device and then  
automatically increments the register address for use on the subsequent command. The “Read” command reads  
one byte of data from the device and the “Read/Address Increment” reads one byte and increments the register  
address automatically. The second byte of the pair is the address or data byte.  
As shown in Figure 36 and Figure 37, SSb should be held low during the entire two byte transfer. Raising SSb  
resets the internal state machine; so, SSb can optionally be raised between each two byte transfers to guarantee  
the state machine will be reinitialized. During a read operation, the SDO becomes active on the falling edge of  
SCLK and the 8-bit contents of the register are driven out MSB first. The SDO is high impedance on the rising edge  
of SS. SDI is a “don’t care” during the data portion of read operations. During write operations, data is driven into  
the device via the SDI pin MSB first. The SDO pin will remain high impedance during write operations. Data always  
transitions with the falling edge of the clock and is latched on the rising edge. The clock should return to a logic  
high when no transfer is in progress.  
The SPI port supports continuous clocking operation where SSb is used to gate two or four byte transfers. The  
maximum speed supported by SPI is 10 MHz.  
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SS  
SCLK  
SDI  
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Instruction Byte  
Address or Write Data  
SDO  
High Impedance  
Figure 36. SPI Write/Set Address Command  
SS  
SCLK  
SDI  
7
6
5
4
3
0
2
1
Read Command  
High Impedance  
6
5
4
3
2
1
0
SDO  
7
Read Data  
Figure 37. SPI Read Command  
7.14.1. Default Device Configuration  
For ease of manufacture and bench testing of the device, the default register settings have been chosen to place  
the device in a fully-functional mode with an easily-observable output clock. Refer to the data sheet for your device.  
7.15. Register Descriptions  
See the device data sheet for a full description of the registers.  
7.16. DSPLLsim Configuration Software  
To simplify frequency planning, loop bandwidth selection, and general device configuration, of the Any-Frequency  
Precision Clocks. Silicon Laboratories has a configuration utility - DSPLLsim for the Si5319, Si5325, Si5326,  
Si5327, Si5367, Si5368 and Si5369. For the Si5374 and Si5375, there is a different configuration utility -  
Si537xDSPLLsim. Both are available to download from www.silabs.com/timing.  
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8. High-Speed I/O  
8.1. Input Clock Buffers  
Any-Frequency Precision Clock devices provide differential inputs for the CKINn clock inputs. These inputs are  
internally biased to a common mode voltage and can be driven by either a single-ended or differential source.  
Figure 38 through Figure 41 show typical interface circuits for LVPECL, CML, LVDS, or CMOS input clocks. Note  
that the jitter generation improves for higher levels on CKINn (within the limits in Table 8, “AC Characteristics—All  
AC coupling the input clocks is recommended because it removes any issue with common mode input voltages.  
However, either ac or dc coupling is acceptable. Figures 38 and 39 show various examples of different input  
termination arrangements.  
Unused inputs should have an AC ground connection. For microprocessor-controlled devices, the PD_CKn bits  
may be set to shut off unused input buffers to reduce power.  
3.3 V  
Si53xx  
130  
130  
C
CKIN+  
300  
40 k  
LVPECL  
Driver  
40 k  
VICM  
±
CKIN _  
82  
82  
C
Figure 38. Differential LVPECL Termination  
3.3 V  
Si53xx  
130  
C
CKIN +  
300  
Driver  
40 k  
40 k  
VICM  
±
CKIN _  
82   
C
Figure 39. Single-Ended LVPECL Termination  
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Si53xx  
C
CKIN +  
300  
40 k  
CML/  
LVDS  
Driver  
100  
40 k  
VICM  
±
CKIN _  
C
Figure 40. CML/LVDS Termination (1.8, 2.5, 3.3 V)  
CMOS Driver  
VDD  
VDD  
VDD  
Si53xx  
R3  
VICM  
150 ohms  
50  
R1  
33 ohms  
R2  
C1  
R5 40 kohm  
CKIN+  
CKIN–  
See Table  
100 nF  
R4  
150 ohms  
R6 40 kohm  
C2  
100 nF  
VDD  
R2  
Notes  
3.3 V  
2.5 V  
1.8 V  
100 ohm  
49.9 ohm  
14.7 ohm  
Locate R1 near CMOS driver  
Locate other components near Si5317  
Recalculate resistor values for other drive strengths  
Additional Notes:  
1. Attenuation circuit limits overshoot and undershoot.  
2. Not to be used with non-square wave input clocks.  
Figure 41. CMOS Termination (1.8, 2.5, 3.3 V)  
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8.2. Output Clock Drivers  
The output clocks can be configured to be compatible with LVPECL, CML, LVDS, or CMOS as shown in Table 56.  
Unused outputs can be left unconnected. For microprocessor-controlled devices, it is recommended to write  
“disable” to SFOUTn to disable the output buffer and reduce power. When the output mode is CMOS, bypass  
mode is not supported.  
Table 56. Output Driver Configuration  
Output Mode  
SFOUTn Pin Settings  
SFOUTn_REG [2:0] Settings  
(Si5316, Si5322, Si5323, Si5365)  
(Si5319, Si5325, SI5326, Si5327,  
Si5367, Si5368, Si5369, Si5374,  
Si5375)  
LVDS  
CML  
HM  
HL  
111  
110  
101  
011  
LVPECL  
MH  
ML  
Low-swing  
LVDS  
CMOS  
Disabled  
Reserved  
LH  
LM  
010  
000  
All Others  
All Others  
Note: The LVPECL outputs are “LVPECL compatible.” No DC biasing circuitry is required to drive a  
standard LVPECL load.  
8.2.1. LVPECL TQFP Output Signal Format Restrictions at 3.3 V (Si5367, Si5368, Si5369)  
The LVPECL and CMOS output formats draw more current than either LVDS or CML; however, there are  
restrictions in the allowed output format pin settings so that the maximum power dissipation for the TQFP devices  
is limited when they are operated at 3.3 V. When Vdd = 3.3 V and there are four enabled LVPECL or CMOS  
outputs, the fifth output must be disabled. When Vdd = 3.3 V and there are five enabled outputs, there can be no  
more than three outputs that are either LVPECL or CMOS. All other configurations are valid, including those with  
Vdd = 2.5 V.  
8.2.2. Typical Output Circuits  
It is recommended that the outputs be ac coupled to avoid common mode issues. This suggestion does not apply  
to the Si5366 and Si5368 when CKOUT5 is configured as FS_OUT (frame sync) because it can a have a duty  
cycle significantly different from 50%.  
Si53xx  
Z0 = 50  
100  
Z0 = 50  
Rcvr  
Figure 42. Typical Output Circuit (Differential)  
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10  
10  
80  
Rcvr  
All resistors are located next to RCVR  
Figure 43. Differential Output Example Requiring Attenuation  
Si53xx  
CMOS  
Logic  
CKOUTn  
Optionally Tie CKOUTn  
Outputs Together for Greater Strength  
Figure 44. Typical CMOS Output Circuit (Tie CKOUTn+ and CKOUTn– Together)  
Unused output drivers should be powered down, per Table 57, or left floating.  
The pin-controlled parts have a DBL2_BY pin that can be used to disable CKOUT2.  
Table 57. Disabling Unused Output Driver  
Output Driver  
Si5365, Si5366  
N/A  
Si5325, Si5326, Si5367, Si5368  
CKOUT1 and CKOUT2  
CKOUT3 and CKOUT4  
CKOUT5/FS_OUT  
Use SFOUT_REG to disable individ-  
ual CKOUTn.  
DBL34  
DBL5/DBL_FS  
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+
Output Disable  
100  
100  
CKOUT+  
CKOUT -  
Figure 45. CKOUT Structure  
8.2.3. Typical Clock Output Scope Shots  
Table 58. Output Format Measurements1,2  
Name  
SFOUT Pin  
SFOUT Code  
Single  
Diff  
Vocm  
Vpk–pk  
Vpk–pk  
Reserved  
LVDS  
HH  
HM  
HLK  
MH  
MM  
ML  
LH  
7
6
5
4
3
2
1
0
.35  
.25  
.75  
.7  
1.2  
3.05  
2.10  
CML  
.5  
LVPECL  
Reserved  
Low Swing LVDS  
CMOS  
1.5  
.5  
.25  
3.3  
1.2  
1.65  
Disable  
LM  
LL  
Reserved  
Notes:  
1. Typical measurements with an Si5326 at V = 3.3 V.  
C
2. For all measurements:  
Vpk-pk on a single output, double the values for differential.  
Vdd = 3.3 V.  
50 ac load to ground.  
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8.3. Typical Scope Shots for SFOUT Options  
Figure 46. sfout_2, CMOS  
Figure 47. sfout_3, lowSwingLVDS  
110  
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Figure 48. sfout_5, LVPECL  
Figure 49. sfout_6, CML  
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Figure 50. sfout_7, LVDS  
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8.4. Crystal/Reference Clock Interfaces (Si5316, Si5319, Si5323, Si5324, Si5326, Si5327,  
Si5366, Si5368, Si5369, Si5374, and Si5375)  
All devices other than the Si5374 and Si5375 can use an external crystal or external clock as a reference. The  
Si5374 and Si5375 are limited to an external reference oscillator and cannot use a crystal. If an external clock is  
used, it must be ac coupled. With appropriate buffers, the same external reference clock can be applied to CKINn.  
Although the reference clock input can be driven single ended (See Figure 51), best performance is with a crystal  
or differential LVPECL source. See Figure 55.  
If the crystal is located close to a fan, it is recommended that the crystal be covered with some type of thermal cap.  
For various crystal vendors and part numbers, see " Appendix A—Narrowband References" on page 119.  
1. For SONET applications, the best jitter performance is with a 114.285 MHz third overtone crystal. The  
Si5327 crystal is fundamental mode and is limited to values between 37 MHz and 41 MHz.  
2. The jitter transfer for the external reference to CKOUT is nearly 1:1 (see " Appendix A—Narrowband  
3. In digital hold or VCO freeze mode, the VCO tracks any changes in the external reference clock.  
3.3 V  
150  
0.1F  
3.3 V  
Si53xx  
10 k  
130   
XA  
XB  
.6 V  
150   
0.1F  
CMOS buffer,  
8mA output current  
For 1.8 V operation, change 130 to 47.5 .  
For 2.5 V operation, change 130 to 82 .  
Figure 51. CMOS External Reference Circuit  
0 dBm into 50  
1.2 V  
Si53xx  
0.01 F  
XA  
10 pF  
0.01 F  
10 k  
0.6 V  
XB  
External Clock Source  
50   
0.1 µF  
Figure 52. Sinewave External Clock Circuit  
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1.2 V  
0.01 F  
XA  
XB  
100   
LVDS, LVPECL, CML, etc.  
10 k  
10 k  
0.6 V  
0.01 F  
Figure 53. Differential External Reference Input Example  
(Not for Si5374 or Si5375)  
Si5374/75  
0.01 F  
OSC-P  
100   
1.2 V  
OSC-N  
LVDS, LVPECL, CML, etc.  
2.5 k  
0.01 F  
0.6 V  
Figure 54. Differential OSC Reference Input Example for Si5374 and Si5375  
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8.5. Three-Level (3L) Input Pins (No External Resistors)  
VDD  
Si53xx  
75 k  
Iimm  
75 k  
External Driver  
Figure 55. Three Level Input Pins  
Parameter  
Input Voltage Low  
Input Voltage Mid  
Input Voltage High  
Input Low Current  
Input Mid Current  
Input High Current  
Symbol  
Vill  
Min  
Max  
.15 x V  
DD  
DD  
Vimm  
Vihh  
Iill  
.45 x Vdd  
.85 x Vdd  
–6 µA  
–2 µA  
.55 x V  
Iimm  
Iihh  
2 µA  
6 µA  
Note: The above currents are the amount of leakage that the 3L inputs can tolerate from an external driver.  
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8.6. Three-Level (3L) Input Pins (With External Resistors)  
VDD  
18 k  
VDD  
Si53xx  
75 k  
Iimm  
18 k  
75 k  
External Driver  
One of eight resistors from a Panasonic EXB-D10C183J  
(or similar) resistor pack  
Figure 56. Three Level Input Pins  
Parameter  
Input Low Current  
Input Mid Current  
Input High Current  
Symbol  
Iill  
Min  
–30 µA  
–11 µA  
Max  
Iimm  
Iihh  
–11 µA  
–30 µA  
Note: The above currents are the amount of leakage that the 3L inputs can tolerate from an external  
driver.  
Any resistor pack may be used.  
The Panasonic EXB-D10C183J is an example.  
PCB layout is not critical.  
Resistor packs are only needed if the leakage current of the external driver exceeds the listed currents.  
If a pin is tied to ground or Vdd, no resistors are needed.  
If a pin is left open (no connect), no resistors are needed.  
116  
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9. Power Supply  
These devices incorporate an on-chip voltage regulator to power the device from supply voltages of 1.8, 2.5, or  
3.3 V. Internal core circuitry is driven from the output of this regulator while I/O circuitry uses the external supply  
voltage directly.  
Figure 57 shows a typical power supply bypass network for the TQFP packages. Figure 58 shows a typical power  
supply bypass network for QFN.  
In both cases, the center ground pad under the device must be electrically and thermally connected to the ground  
plane.  
0.1 uF  
System  
C1 – C8  
Power  
Supply  
(1.8, 2.5 or  
3.3 V)  
1.0 uF  
Ferrite  
Bead  
C9  
Ferrite bead is Venkel BC1206-471H  
or equivalent.  
VDD  
GND  
TQFP  
PKG  
Figure 57. Typical Power Supply Bypass Network (TQFP Package)  
0.1 uF  
System  
C1 – C3  
Power  
Supply  
(1.8, 2.5, or  
3.3 V)  
1.0 uF  
Ferrite  
Bead  
C4  
Ferrite bead is Venkel BC1206-471H  
or equivalent.  
VDD  
GND  
QFN  
PKG  
Figure 58. Typical Power Supply Bypass Network (QFN Package)  
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10. Packages and Ordering Guide  
Refer to the respective data sheet for your device packaging and ordering information.  
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APPENDIX A—NARROWBAND REFERENCES  
Resonator/External Clock Selection  
Table 59 shows the 114.285 MHz third overtone crystals that have been approved for use with the Si53xx jitter  
attenuating clocks.  
Table 59. Approved Crystals  
Manufacturer  
Part Number  
Web Site  
Stability  
Initial  
Accuracy  
TXC  
Connor Winfield  
Connor Winfield  
NDK  
7MA1400014  
CS-018  
100 ppm  
100 ppm  
20 ppm  
100 ppm  
20 ppm  
20 ppm  
100 ppm  
100 ppm  
20 ppm  
100 ppm  
20 ppm  
20 ppm  
CS-023  
EXS00A-CS00871  
EXS00A-CS00997  
NDK  
Siward  
XTL573200NLG-  
114.285 MHz-OR  
Saronix/eCera  
Mtron  
FLB420001  
100 ppm  
100 ppm  
100 ppm  
100 ppm  
M1253S071  
Table 60. XA/XB Reference Sources and Frequencies  
RATE[1:0]  
HH  
NB/WB  
Type  
No crystal or external clock  
Reserved  
Recommended  
Lower limit  
Upper limit  
WB  
NB  
NB  
NB  
NB  
NB  
NB  
NB  
NB  
HM  
HL  
Reserved  
MH  
External clock  
114.285 MHz  
114.285 MHz  
109 MHz  
125.5 MHz  
MM  
ML  
3rd overtone crystal  
Reserved  
LH  
Reserved  
LM  
External clock  
38.88 MHz  
40 MHz  
37 MHz  
37 MHz  
41 MHz  
41 MHz  
LL  
Fundamental mode crystal  
In some applications, a crystal with frequencies other than 114.285 MHz may be used. Contact Silicon Labs for  
details and a current list of crystal vendors and approved part numbers.  
External reference (and crystal) frequency values should be avoided that result in an output frequency that is an  
integer or near integer multiple of the reference frequency. See Appendix B for details.  
Because the crystal is used as a jitter reference, rapid changes of the crystal temperature can temporarily disturb  
the output phase and frequency. For example, it is recommended that the crystal not be placed close to a fan that  
is being turned off and on. If a situation such as this is unavoidable, the crystal should be thermally isolated with an  
insulating cover.  
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Fundamental Mode Crystals  
For cost sensitive applications that do not have the most demanding jitter requirements, all of the narrow band  
devices can use fundamental mode crystals that are in the lowest frequency band ranging from 37 to 41 MHz  
(corresponding to RATE = LL). Unlike the other narrowband members of the family, the Si5327 is only capable of  
using fundamental mode crystals that are in this range. For a more detailed discussion of the trade-offs associated  
with this approach and a list of approved low frequency crystals, please see the application note AN591, which can  
be downloaded from www.silabs.com/timing.  
Reference Drift  
During Digital Hold, long-term and temperature related drift of the reference input result in a one-to-one drift of the  
output frequency. That is, the stability of the any-frequency output is identical to the drift of the reference frequency.  
This means that for the most demanding applications where the drift of a crystal is not acceptable, an external  
temperature compensated or ovenized oscillator will be required. Drift is not an issue unless the device is in Digital  
Hold. Also, the initial accuracy of the reference oscillator (or crystal) is not relevant as long as it is within one of the  
frequency bands described in Table 60.  
Reference Jitter  
Jitter on the reference input has a roughly one-to-one transfer function to the output jitter over the band from  
100 Hz up to about 30 kHz. If the XA/XB pins implement a crystal oscillator, the reference will have suitably low  
jitter if a suitable crystal is used. If the XA/XB pins are connected to an external reference oscillator, the jitter of the  
external reference oscillator may also contribute significantly to the output jitter. A typical reference input-to-output  
jitter transfer function is shown in Figure 59.  
38.88MHz XO, 38.88MHz CKIN, 38.88MHz CKOUT  
10  
0
-10  
-20  
-30  
Jitter Xfer  
1
10  
100  
1000  
10000 100000 1000000  
Frequency (Hz)  
Figure 59. Typical Reference Jitter Transfer Function  
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APPENDIX B—FREQUENCY PLANS AND JITTER PERFORMANCE (Si5316, Si5319,  
Si5323, SI5324, Si5326, Si5327, Si5366, Si5368, Si5369, Si5374, Si5375)  
Introduction  
To achieve the best jitter performance from Narrowband Any-Frequency Clock devices, a few general guidelines  
should be observed:  
High f3 Value  
f3 is defined as the comparison frequency at the Phase Detector. It is equal to the input frequency divided by N3.  
DSPLLsim automatically picks the frequency plan that has the highest possible f3 value and it reports f3 for every  
new frequency plan that it generates. f3 has a range from 2 kHz minimum up to 2 MHz maximum. The two main  
causes of a low f3 are a low clock input frequency (which establishes an upper bound on f3) and a PLL multiplier  
ratio that is comprised of large and mutually prime nominators and denominators. Specifically, for  
CKOUT = CKIN x (P/Q), if P and Q are mutually prime and large in size, then f3 may have a low value. Very low  
values of f3 usually result in extra jitter as can be seen in Figure 60.  
Phase Noise versus f3, 155.52 MHz in, 622.08 MHz out  
0
-20  
1709 kHz  
-40  
-60  
855 kHz  
427 kHz  
214 kHz  
107 kHz  
54 kHz  
27 kHz  
13 kHz  
7 kHz  
-80  
-100  
-120  
-140  
-160  
3 kHz  
10  
100  
1000  
10000 100000 1000000 1E+07  
1E+08  
Frequency (Hz)  
Figure 60. Jitter vs. f3  
For the f3 study, the input, output and DCO frequencies were held constant while the dividers were manipulated by  
hand to artificially reduce the value of f3. Two effects can be seen as f3 approaches the 2 kHz lower limit: there are  
“spur like” spikes in the mid-band and the noise floor is elevated at the near end. It is also clear that once f3 is  
above roughly 50 kHz, there is very little benefit from further increasing f3. Note that the loop bandwidth for this  
study was 60 Hz and any noise below 60 Hz is a result of the input clock, not the Any-Frequency Precision Clock.  
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Figure 61 shows similar results and ties them to RMS jitter values. It also helps to illustrate one potential remedy  
for solutions with low f3. Note that 38.88 MHz x 5 = 194.4 MHz. In this case, an FPGA was used to multiply a  
38.88 MHz input clock up by a factor of five to 194.4 MHz, using a feature such as the Xilinx DCM (Digital Clock  
Manager). Even though FPGAs are notorious for having jittered outputs, the jitter attenuating feature of the  
Narrowband Any-Frequency Clocks allow an FPGA’s output to be used to produce a very clean clock, as can be  
seen from the jitter numbers below.  
38.88 MHz in, 194.4 MHz in, 690.57 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
10  
100  
1000  
10000  
100000  
1000000 10000000 100000000  
Offset Frequency (Hz)  
Dark blue—38.88 MHz in, f3 = 3.214 kHz  
Light blue—194.4 MHz in, f3 = 16.1 kHz  
Figure 61. Jitter vs. f3 with FPGA  
Table 61. Jitter Values for Figure 61  
f3 = 3.214 kHz  
f3 = 16.1 kHz  
CKIN = 38.88 MHz  
Jitter, RMS  
1,034 fs  
CKIN = 194.4 MHz  
Jitter, RMS  
285 fs  
Jitter Bandwidth  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
800 Hz to 80 MHz  
668 fs  
300 fs  
169 fs  
168 fs  
374 fs  
287 fs  
3,598 fs  
378 fs  
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Reference vs. Output Frequency  
Because of internal coupling, output frequencies that are an integer multiple (or close to an integer multiple) of the  
XA/XB reference frequency (either internal or external) should be avoided. Figure 62 illustrates this by showing a  
38.88 MHz reference being used to generate both a 622.08 MHz output (which is an integer multiple of 38.88 MHz)  
and 696.399 MHz (which is not an integer multiple of 38.88 MHz). Notice the mid-band spurs on the 622.08 MHz  
output, which contribute to the RMS phase noise for the SONET jitter masks. Their effect is more pronounced for  
the broadband case. For more information on this effect, see "Appendix G—Near Integer Ratios" on page 162.  
155.52 MHz in, 622.08 MHz out, 696.399 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Yellow—696.399 MHz output  
Blue—622.08 MHz output  
Figure 62. Reference vs. Output Frequency  
Table 62. Jitter Values for Figure 62  
696.399 MHz Out  
622.08 MHz Out  
Jitter Bandwidth  
Yellow, fs RMS  
Blue, fs RMS  
679  
SONET_OC48, 12 kHz to 20 MHz  
SONET_OC192_A, 20 kHz to 80 MHz  
SONET_OC192_B, 4 MHz to 80 MHz  
SONET_OC192_C, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
379  
393  
210  
373  
484  
520  
191  
392  
1,196  
The crystal frequency of 114.285 MHz was picked for its lack of integer relationship to most of the expected output  
frequencies. If, for instance, an output frequency of 457.14 MHz (= 4 x 114.285 MHz) were desired, it would be  
preferable not to use the 114.285 MHz crystal as the reference. For a more detailed study of this, see "Appendix  
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High Reference Frequency  
When selecting a reference frequency, with all other things being equal, the higher the reference frequency, the  
lower the output jitter. Figures 63 and 64 illustrate this. For a discussion of the available reference frequencies, see  
37 MHz thru 163 MHz Ext Ref, 155.52 MHz in, 622.08 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Dark Blue—37 MHz  
Violet—55 MHz  
Light Blue—109 MHz  
Yellow-Green—163 MHz  
Figure 63. Jitter vs. Reference Frequency (1 of 2)  
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41 MHz thru 180 MHz Ext Ref, 155.52 MHz in, 622.08 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Dark Blue—41 MHz  
Light Blue—61 MHz  
Red—125.5 MHz  
Green—180 MHz  
Figure 64. Jitter vs. Reference Frequency (2 of 2)  
All phase noise numbers are in fs, RMS  
External Reference Frequency:  
Jitter Bandwidth:  
37  
41  
55  
61  
109  
MHz  
330  
125.5  
MHz  
321  
163  
MHz  
292  
180  
MHz  
298  
MHz  
1092  
MHz  
858  
MHz  
633  
MHz  
715  
SONET_OC48, 12 kHz to 20 MHz  
SONET_OC192_A, 20 kHz to 80 MHz  
SONET_OC192_B, 4 MHz to 80 MHz  
1086  
226  
855  
229  
639  
232  
698  
221  
356  
217  
335  
183  
325  
221  
331  
226  
SONET_OC192_C, 50 kHz to 80 MHz  
BroadBand, 800 Hz to 80 MHz  
1028  
1165  
797  
956  
597  
728  
651  
773  
340  
423  
316  
375  
314  
393  
320  
393  
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APPENDIX C—TYPICAL PHASE NOISE PLOTS  
Introduction  
The following are some typical phase noise plots. The clock input source is a Rohde and Schwarz model SML03  
RF Generator. Except as noted, the phase noise analysis equipment is the Agilent E5052B. Also (except as noted),  
the Any-Frequency part was an Si5326 operating at 3.3 V with an ac-coupled differential PECL output and an ac-  
coupled differential sine wave input from the RF generator at 0 dBm. Note that, as with any PLL, the output jitter  
that is below the loop bandwidth of the Any-Frequency device is caused by the jitter of the input clock, not the Any-  
Frequency Precision Clock. Except as noted, the loop bandwidths were 60 Hz to 100 Hz.  
Figure 65. 155.52 MHz In; 622.08 MHz Out  
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Figure 66. 155.52 MHz In; 622.08 MHz Out; Loop BW = 7 Hz, Si5324  
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Figure 67. 19.44 MHz In; 156.25 MHz Out; Loop BW = 80 Hz  
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Figure 68. 19.44 MHz In; 156.25 MHz Out; Loop BW = 5 Hz, Si5324  
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Figure 69. 27 MHz In; 148.35 MHz Out; Light Trace BW = 6 Hz; Dark Trace BW = 110 Hz, Si5324  
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Figure 70. 61.44 MHz In; 491.52 MHz Out; Loop BW = 7 Hz, Si5324  
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Figure 71. 622.08 MHz In; 672.16 MHz Out; Loop BW = 6.9 kHz  
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Figure 72. 622.08 MHz In; 672.16 MHz Out; Loop BW = 100 Hz  
Rev. 0.5  
133  
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Si53xx-RM  
Figure 73. 156.25 MHz In; 155.52 MHz Out  
134  
Rev. 0.5  
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Si53xx-RM  
Figure 74. 78.125 MHz In; 644.531 MHz Out  
Table 63. Jitter Values for Figure 74  
Jitter Bandwidth  
644.531 MHz  
Jitter (RMS)  
Broadband, 1 kHz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
223 fs  
246 fs  
244 fs  
120 fs  
234 fs  
248 fs  
Rev. 0.5  
135  
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Si53xx-RM  
Figure 75. 78.125 MHz In; 690.569 MHz Out  
Table 64. Jitter Values for Figure 75  
Jitter Bandwidth  
690.569 MHz  
Jitter (RMS)  
Broadband, 1 kHz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
244 fs  
260 fs  
261 fs  
120 fs  
253 fs  
266 fs  
136  
Rev. 0.5  
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Si53xx-RM  
Figure 76. 78.125 MHz In; 693.493 MHz Out  
Table 65. Jitter Values for Figure 76  
Jitter Bandwidth  
693.493 MHz  
Jitter (RMS)  
Broadband, 1 kHz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
243 fs  
265 fs  
264 fs  
124 fs  
255 fs  
269 fs  
Rev. 0.5  
137  
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Si53xx-RM  
86.685 MHz in, 173.371 MHz and 693.493 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Red = 693.493 MHz  
Blue = 173.371 MHz  
Figure 77. 86.685 MHz In; 173.371 MHz and 693.493 MHz Out  
Table 66. Jitter Values for Figure 77  
Jitter Bandwidth  
173.371 MHz  
Jitter (RMS)  
693.493 MHz  
Jitter (RMS)  
Broadband, 1 kHz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
262 fs  
297 fs  
309 fs  
196 fs  
301 fs  
313 fs  
243 fs  
265 fs  
264 fs  
124 fs  
255 fs  
269 fs  
138  
Rev. 0.5  
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Si53xx-RM  
Figure 78. 86.685 MHz In; 173.371 MHz Out  
Rev. 0.5  
139  
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Si53xx-RM  
Figure 79. 86.685 MHz In; 693.493 MHz Out  
140  
Rev. 0.5  
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Si53xx-RM  
155.52 MHz and 156.25MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Blue = 155.52 MHz  
Red = 156.25 MHz  
Figure 80. 155.52 MHz and 156.25 MHz In; 622.08 MHz Out  
Table 67. Jitter Values for Figure 80  
Jitter Bandwidth  
155.52 MHz Input  
Jitter (RMS)  
156.25 MHz Input  
Jitter (RMS)  
4507 fs  
251 fs  
Broadband, 100 Hz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
4432 fs  
249 fs  
274 fs  
166 fs  
267 fs  
274 fs  
271 fs  
164 fs  
262 fs  
363 fs  
Rev. 0.5  
141  
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Si53xx-RM  
Figure 81. 10 MHz In; 1 GHz Out  
142  
Rev. 0.5  
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Si53xx-RM  
Digital Video (HD-SDI)  
27 MHz in, 148.5 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
10  
100  
1000  
10000  
100000  
1000000 10000000 100000000  
Offset Frequency (Hz)  
Jitter Band  
Jitter  
2.42 ps, RMS  
14.0 ps  
Brick Wall, 10 Hz to 20 MHz  
Peak-to-peak  
Phase noise equipment: Agilent model JS500.  
Rev. 0.5  
143  
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Si53xx-RM  
APPENDIX D—ALARM STRUCTURE  
LOS_INT  
LOS1_INT  
LOS2_INT  
FOS1_INT  
LOSX_FLG  
LOSX_MSK  
in  
in  
in  
out  
out  
out  
Sticky  
Write 0  
to clear  
INT_POL  
LOS1_FLG  
LOS1_MSK  
Sticky  
Write 0  
to clear  
LOS2_FLG  
LOS2_MSK  
Sticky  
Write 0  
to clear  
FOS1_FLG  
FOS1_MSK  
in  
out  
Sticky  
Write 0  
to clear  
FOS2_INT  
LOL_INT  
FOS2_FLG  
FOS2_MSK  
in  
out  
Sticky  
Write 0  
to clear  
LOL_FLG  
LOL_MSK  
in  
out  
Sticky  
Write 0  
to clear  
WIDEBAND MODE  
LOS1-EN  
LOS1_INT  
LOS  
CKIN1  
Detector  
CK_BAD_POL  
1
0
INT_C1B  
PD_CK1  
E
FOS  
Detector  
FOS1_EN  
INT_PIN  
CK1_BAD_PIN  
FOS_EN  
LOS2_EN  
LOS2_INT  
LOS  
CKIN2  
Detector  
CK_BAD_POL  
PD_CK2  
C2B  
FOS2_INT  
FOS  
E
Detector  
FOS2_EN  
CK2_BAD_PIN  
FOS_EN  
Figure 82. Si5324 and Si5326 Alarm Diagram  
144  
Rev. 0.5  
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Si53xx-RM  
LOSX_FLG  
LOSX_MSK  
LOS_INT  
LOS1_INT  
LOS2_INT  
LOS3_INT  
LOS4_INT  
FOS1_INT  
FOS2_INT  
FOS3_INT  
FOS4_INT  
ALIGN_INT  
LOL_INT  
in  
in  
in  
in  
in  
in  
in  
in  
in  
in  
in  
out  
out  
out  
out  
out  
out  
out  
out  
out  
out  
out  
Sticky  
Write 0  
to clear  
INT_POL  
LOS1_FLG  
LOS1_MSK  
Sticky  
Write 0  
to clear  
LOS2_FLG  
LOS2_MSK  
Sticky  
Write 0  
to clear  
LOS3_FLG  
LOS3_MSK  
Sticky  
Write 0  
to clear  
LOS4_FLG  
LOS4_MSK  
Sticky  
Write 0  
to clear  
FOS1_FLG  
FOS1_MSK  
Sticky  
Write 0  
to clear  
FOS2_FLG  
FOS2_MSK  
Sticky  
Write 0  
to clear  
FOS3_FLG  
FOS3_MSK  
Sticky  
Write 0  
to clear  
FOS4_FLG  
FOS4_MSK  
Sticky  
Write 0  
to clear  
ALIGN_FLG  
ALIGN_MSK  
Sticky  
Write 0  
to clear  
LOL_FLG  
LOL_MSK  
Sticky  
Write 0  
to clear  
WIDEBAND MODE  
To Next Page  
CK_BAD_POL  
LOS4_EN  
LOS4_INT  
CK_CONFIG_REG  
CKIN4  
LOS  
Detector  
1
0
INT_ALM  
PD_CK4  
ALIGN_INT  
E
1
0
FOS  
Detector  
FOS4_EN  
INT_PIN  
ALRMOUT_PIN  
FOS_EN  
Figure 83. Si5368 Alarm Diagram (1 of 2)  
Rev. 0.5  
145  
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Si53xx-RM  
LOS3_EN  
LOS3_INT  
CKIN3  
LOS  
Detector  
CK_BAD_POL  
PD_CK3  
C3B  
FOS  
E
Detector  
FOS3_EN  
FOS_EN  
LOSI_EN  
LOS1_INT  
CKIN1  
LOS  
Detector  
PD_CK1  
1
0
C1B  
E
FOS  
Detector  
FOSI_EN  
FOS_EN  
CK_CONFIG_REG  
FSYNC_SWTCH_REG  
LOS2_EN  
LOS4_INT  
LOS2_INT  
CKIN2  
LOS  
Detector  
PD_CK2  
1
0
C2B  
E
FOS  
Detector  
FOS2_EN  
FOS_EN  
Figure 84. Si5368 Alarm Diagram (2 of 2)  
146  
Rev. 0.5  
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Si53xx-RM  
APPENDIX E—INTERNAL PULLUP, PULLDOWN BY PIN  
Tables 68–79 show which 2-Level CMOS pins have pullups or pulldowns. Note the value of the pullup/pulldown  
resistor is typically 75 k.  
Table 68. Si5316 Pullup/Down  
Pin #  
1
Si5316  
RST  
Pull?  
U
RATE0  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
11  
DBL2_BY  
RATE1  
14  
15  
21  
22  
23  
24  
25  
26  
27  
30  
33  
CS  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
CK1DIV  
CK2DIV  
SFOUT1  
SFOUT0  
Table 69. Si5322 Pullup/Down  
Pin #  
1
Si5322  
RST  
Pull?  
U
2
FRQTBL  
AUTOSEL  
DBL2_BY  
CS_CA  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
9
14  
21  
22  
23  
24  
25  
26  
27  
30  
33  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
SFOUT0  
Rev. 0.5  
147  
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Si53xx-RM  
Table 70. Si5323 Pullup/Down  
Pin #  
1
Si5323  
RST  
Pull?  
U
2
FRQTBL  
AUTOSEL  
RATE0  
U, D  
U, D  
U, D  
U, D  
U, D  
D
9
11  
14  
15  
19  
20  
21  
22  
23  
24  
25  
26  
27  
30  
33  
DBL2_BY  
RATE1  
DEC  
INC  
D
CS_CA  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
BWSEL0  
BWSEL1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
SFOUT0  
Table 71. Si5319, Si5324, Pullup/Down  
Pin #  
1
Si5326  
RST  
Pull?  
U
11  
RATE0  
RATE1  
CS_CA  
SCL  
U, D  
U, D  
U, D  
D
15  
21  
22  
24  
25  
26  
27  
36  
A0  
D
A1  
D
A2_SS  
SDI  
D
D
CMODE  
U, D  
148  
Rev. 0.5  
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Si53xx-RM  
Table 72. Si5325 Pullup/Down  
Pin #  
1
Si5325  
RST  
Pull?  
U
21  
22  
24  
25  
26  
27  
36  
CS_CA  
SCL  
U, D  
D
A0  
D
A1  
D
A2_SS  
SDI  
D
D
CMODE  
U, D  
Table 73. Si5326 Pullup/Down  
Pin #  
1
Si5326  
RST  
Pull?  
U
11  
RATE0  
RATE1  
DEC  
U, D  
U, D  
D
15  
19  
20  
21  
22  
24  
25  
26  
27  
36  
INC  
D
CS_CA  
SCL  
U, D  
D
A0  
D
A1  
D
A2_SS  
SDI  
D
D
CMODE  
U, D  
Rev. 0.5  
149  
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Si53xx-RM  
Table 74. Si5327 Pullup/Down  
Pin #  
1
Si5327  
RST  
Pull?  
U
11  
RATE0  
RATE1  
CS  
U, D  
U, D  
U, D  
D
15  
21  
22  
24  
25  
26  
27  
36  
SCL  
A0  
D
A1  
D
A2_SS  
SDI  
D
D
CMODE  
U, D  
Table 75. Si5365 Pullup/Down  
Pin #  
3
Si5365  
RST  
Pull?  
U
4
FRQTBL  
CS0_C3A  
AUTOSEL  
DBL2_BY  
DSBL5  
U, D  
D
13  
22  
37  
50  
57  
60  
61  
66  
67  
68  
69  
70  
71  
80  
85  
95  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U
CS1_C4A  
BWSEL0  
BWSEL1  
DIV34_0  
DIV34_1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
DBL34  
SFOUT0  
U, D  
150  
Rev. 0.5  
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Table 76. Si5366 Pullup/Down  
Pin #  
3
Si5366  
RST  
Pull?  
U
4
FRQTBL  
CS0_C3A  
FS_SW  
U, D  
D
13  
20  
21  
22  
32  
37  
42  
50  
51  
54  
55  
56  
57  
60  
61  
66  
67  
68  
69  
70  
71  
80  
85  
95  
D
FS_ALIGN  
AUTOSEL  
RATE0  
D
U, D  
U, D  
U, D  
U, D  
U, D  
D
DBL2_BY  
RATE1  
DBL_FS  
CK_CONF  
DEC  
D
INC  
D
FOS_CTL  
CS1_C4A  
BWSEL0  
BWSEL1  
DIV34_0  
DIV34_1  
FRQSEL0  
FRQSEL1  
FRQSEL2  
FRQSEL3  
SFOUT1  
DSBL34  
SFOUT0  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U, D  
U
U, D  
Rev. 0.5  
151  
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Si53xx-RM  
Table 77. Si5367 Pullup/Down  
Pin #  
3
Si5367  
RST  
Pull?  
U
13  
57  
60  
68  
69  
70  
71  
90  
CS0_C3A  
CS1_C4A  
SCL  
D
U, D  
D
A0  
D
A1  
D
A2_SSB  
SDI  
D
D
CMODE  
U, D  
Table 78. Si5368 Pullup/Down  
Pin #  
3
Si5368  
RST  
Pull?  
U
13  
21  
32  
42  
54  
55  
57  
60  
68  
69  
70  
71  
90  
CS0_C3A  
FS_ALIGN  
RATE0  
RATE1  
DEC  
D
D
U, D  
U, D  
D
INC  
D
CS1_C4A  
SCL  
U, D  
D
A0  
D
A1  
D
A2_SSB  
SDI  
D
D
CMODE  
U, D  
152  
Rev. 0.5  
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Si53xx-RM  
Table 79. Si5369 Pullup/Down  
Pin #  
3
Si5368  
RST  
Pull?  
U
13  
21  
32  
42  
57  
60  
68  
69  
70  
71  
90  
CS0_C3A  
FS_ALIGN  
RATE0  
RATE1  
CS1_C4A  
SCL  
D
D
U, D  
U, D  
U, D  
D
A0  
D
A1  
D
A2_SSB  
SDI  
D
D
CMODE  
U, D  
Table 80. Si5374/75 Pullup/Down  
Pin #  
D4  
D6  
F6  
Si5374/75  
RSTL_A  
RSTL_B  
RSTL_C  
RSTL_D  
CS_CA_A  
CS_CA_B  
CS_CA_C  
CS_CA_A  
SCL  
Pull?  
U
U
U
F4  
U
D1  
A6  
F9  
U/D  
U/D  
U/D  
U/D  
D
J4  
G5  
Rev. 0.5  
153  
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Si53xx-RM  
APPENDIX F—TYPICAL  
PERFORMANCE: BYPASS  
MODE, PSRR,  
CROSSTALK, OUTPUT FORMAT JITTER  
This appendix is divided into the following four sections:  
Bypass Mode Performance  
Power Supply Noise Rejection  
Crosstalk  
Output Format Jitter  
Bypass: 622.08 MHz In, 622.08 MHz Out  
622.08 MHz in, 622.08 MHz out  
-60  
-70  
-80  
-90  
-100  
-110  
-120  
-130  
-140  
-150  
-160  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Dark blue — normal, locked  
Light blue — digital hold  
Pink — bypass  
Green — Marconi RF generator  
Normal,  
Locked  
In Digital Hold  
In Bypass  
Marconi RF  
Source  
Jitter Bandwidth  
Jitter (RMS)  
296 fs  
Jitter (RMS)  
294 fs  
Jitter (RMS)  
2,426 fs  
2,281 fs  
3,079fs  
Jitter (RMS)  
249 fs  
Broadband, 1000 Hz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192,4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
303 fs  
304 fs  
236 fs  
321 fs  
319 fs  
352 fs  
169 fs  
165 fs  
2,621 fs  
3,078 fs  
3,076 fs  
305 fs  
304 fs  
303 fs  
340 fs  
329 fs  
325 fs  
370 fs  
154  
Rev. 0.5  
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Si53xx-RM  
Power Supply Noise Rejection  
Power Supply Noise to Output Transfer Function  
-60  
-65  
-70  
-75  
-80  
-85  
-90  
-95  
-100  
-105  
1
10  
100  
1000  
kHz  
38.88 MHz in, 155.52 MHz out; Bandwidth = 110 Hz  
Rev. 0.5  
155  
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Si53xx-RM  
Clock Input Crosstalk Results: Test Conditions  
Jitter Band  
155.52 MHz in, 155.521 MHz in, 155.521 MHz in, 155.521 MHz in, 155.521 MHz in,  
622 MHz out,  
For reference,  
No crosstalk  
622.084 MHz  
out,  
622.084 MHz  
out,  
622.084 MHz  
out,  
622.084 MHz  
out,  
No crosstalk  
155.52 MHz  
Xtalk,  
155.52 MHz  
Xtalk,  
155.52 MHz  
Xtalk,  
99 Hz loop  
Bandwidth  
6.72 kHz loop  
Bandwidth  
In digital hold  
OC-48,  
12 kHz to 20 MHz  
262 fs  
287 fs  
285 fs  
262 fs  
290 fs  
289 fs  
269 fs  
296 fs  
298 fs  
422 fs  
255 fs  
OC-192,  
20 kHz to 80 MHz  
366 fs  
280 fs  
Broadband,  
1,010 fs  
277 fs  
800 Hz to 80 MHz  
Measurement conditions:  
1. Using Si5365/66-EVB.  
2. Clock input on CKIN1, a 0dBm sine wave from Rohde and Schwarz RF Generator, model SML03  
3. Crosstalk interfering signal applied to CKIN3, a PECL output at 155.52 MHz  
4. All differential, AC coupled signals  
156  
Rev. 0.5  
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Si53xx-RM  
Clock Input Crosstalk: Phase Noise Plots  
1 55 .52 1 M H z in , 6 2 2 .0 8 4 M H z o u t  
0
-2 0  
-4 0  
-6 0  
-8 0  
-10 0  
-12 0  
-14 0  
-16 0  
-18 0  
1 00  
10 0 0  
1 0 0 00  
1 0 00 0 0  
1 00 0 0 00  
1 0 0 00 0 0 0  
1 0 0 00 0 0 00  
O ffs e t F re q u e n c y (H z)  
Dark blue — No crosstalk  
Light blue — With crosstalk, low bandwidth  
Yellow — With crosstalk, high bandwidth  
Red — With crosstalk, in digital hold  
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Clock Input Crosstalk: Detail View  
155.521 MHz in, 622.084 MHz out  
-60  
-70  
-80  
-90  
-100  
-110  
-120  
-130  
100  
1000  
10000  
100000  
Offset Frequency (Hz)  
Dark blue — No crosstalk  
Light blue — With crosstalk, low bandwidth  
Yellow — With crosstalk, high bandwidth  
Red — With crosstalk, in digital hold  
158  
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Clock Input Crosstalk: Wideband Comparison  
155.521 M H z in, 622.084 M H z out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
-180  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Dark blue — Bandwidth = 6.72 kHz; no Xtalk  
Light blue — Bandwidth = 6.72 kHz; with Xtalk  
Jitter Band  
Jitter, w/ Xtlk  
303 fs RMS  
316 fs RMS  
340 fs RMS  
Jitter, no Xtlk  
422 fs RMS  
366 fs RMS  
1,010 fs RMS  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
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Clock Input Crosstalk: Output of Rohde and Schwartz RF  
Rohde and Schwarz: 155.521 MHz  
-60  
-70  
-80  
-90  
-100  
-110  
-120  
100  
1000  
Offset Frequency (Hz)  
160  
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Jitter vs. Output Format: 19.44 MHz In, 622.08 MHz Out  
19.44 MHz in, 622.08 MHz out  
0
-20  
-40  
-60  
-80  
-100  
-120  
-140  
-160  
100  
1000  
10000  
100000  
1000000  
10000000  
100000000  
Offset Frequency (Hz)  
Spectrum Analyzer: Agilent Model E444OA  
Table 81. Output Format vs. Jitter  
Bandwidth  
LVPECL Jitter  
(RMS)  
LVDS Jitter  
(RMS)  
CML Jitter (RMS) Low Swing LVDS  
Jitter (RMS)  
Broadband, 1 kHz to 10 MHz  
OC-48, 12 kHz to 20 MHz  
OC-192, 20 kHz to 80 MHz  
OC-192, 4 MHz to 80 MHz  
OC-192, 50 kHz to 80 MHz  
Broadband, 800 Hz to 80 MHz  
282 fs  
297 fs  
315 fs  
180 fs  
299 fs  
325 fs  
269 fs  
289 fs  
327 fs  
222 fs  
313 fs  
332 fs  
257 fs  
290 fs  
358 fs  
277 fs  
348 fs  
357 fs  
261 fs  
291 fs  
362 fs  
281 fs  
351 fs  
360 fs  
Rev. 0.5  
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APPENDIX G—NEAR INTEGER RATIOS  
To provide more details and to provide boundaries with respect to the “Reference vs. Output Frequency” issue  
described in Appendix B on page 121, the following study was performed and is presented below.  
Test Conditions  
XA/XB External Reference held constant at 38.88 MHz  
Input frequency centered at 155.52 MHz, then scanned.  
Scan Ranges and Resolutions:  
± 50 ppm with 2 ppm steps  
± 200 ppm with 10 ppm steps  
± 2000 ppm with 50 ppm steps  
Output frequency always exactly four times the input frequency  
Centered at 622.08 MHz  
Jitter values are RMS, integrated from 800 Hz to 80 MHz  
38.88 MHz External XA-XB Reference  
1200  
1000  
800  
600  
400  
200  
0
155.51  
155.515  
155.52  
155.525  
155.53  
Input Frequency (MHz)  
Input Frequency Variation = ±50 ppm  
Figure 85. ±50 ppm, 2 ppm Steps  
162  
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38.88 MHz External XA-XB Reference  
1200  
1000  
800  
600  
400  
200  
0
155.49  
155.5  
155.51  
155.52  
155.53  
155.54  
155.55  
Input Frequency (MHz)  
Input Frequency  
Figure 86. ±200 ppm, 10 ppm Steps  
38.88 MHz External XA-XB Reference  
1200  
1000  
800  
600  
400  
200  
0
155.2 155.3 155.3 155.4 155.4 155.5 155.5 155.6 155.6 155.7 155.7 155.8 155.8 155.9 155.9  
Input Frequency (MHz)  
Input Frequency Variation = ±2000 ppm  
Figure 87. ±2000 ppm, 50 ppm Steps  
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APPENDIX H—JITTER ATTENUATION AND LOOP BW  
The following illustrates the effects of different loop BW values on the jitter attenuation of the Any-Frequency  
devices. The jitter consists of sine wave modulation at varying frequencies. The RMS jitter values of the modulated  
sine wave input is compared to the output jitter of an Si5326 and an Si5324. For reference, the top entry in the  
table lists the jitter without any modulation. For each entry in the table, the corresponding phase noise plots are  
presented.  
Table 82. Jitter Values  
Fmod  
0
Fdev  
0
Jitter Start  
500 Hz  
10 Hz  
RF Gen  
1.18 ps  
181 ps  
177 ps  
175 ps  
184 ps  
138 ps  
139 ps  
Si5326  
283 fs  
169 ps  
136 ps  
18.6 ps  
4.28 ps  
297 fs  
302 fs  
Si5324  
281 fs  
10.6 ps  
2.04 ps  
295 fs  
292 fs  
302 fs  
304 fs  
50 Hz  
100 Hz  
500 Hz  
1 kHz  
5 kHz  
10 kHz  
50 Hz  
100 Hz  
500 Hz  
1 kHz  
5 kHz  
10 kHz  
50 Hz  
100 Hz  
500 Hz  
500 Hz  
500 Hz  
Notes:  
1. All phase noise plots are with 622.08 MHz input and 622.08 MHz output.  
Si5326 bandwidth = 120 Hz; Si5324 bandwidth = 7 Hz.  
2. FM modulation at F = Fmod with modulation amplitude = Fdev.  
3. Jit start is the start of the brick wall integration band. All integration bands end at 50 MHz.  
4. Phase noise measured by Agilent model E5052B.  
5. RF Generator was Rohde and Schwarz model SML03.  
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622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06 1.00E+07 1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 88. RF Generator, Si5326, Si5324; No Jitter (For Reference)  
622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06 1.00E+07 1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Figure 89. RF Generator, Si5326, Si5324 (50 Hz Jitter)  
Rev. 0.5  
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622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06 1.00E+07 1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 90. RF Generator, Si5326, Si5324 (100 Hz Jitter)  
622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 91. RF Generator, Si5326, Si5324 (500 Hz Jitter)  
166  
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622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 92. RF Generator, Si5326, Si5324 (1 kHz Jitter)  
622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 93. RF Generator, Si5326, Si5324 (5 kHz Jitter)  
Rev. 0.5  
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622.08 MHz in, 622.08 MHz out  
0.00E+00  
-2.00E+01  
-4.00E+01  
-6.00E+01  
-8.00E+01  
-1.00E+02  
-1.20E+02  
-1.40E+02  
-1.60E+02  
-1.80E+02  
1.00E+02  
1.00E+03  
1.00E+04  
1.00E+05  
1.00E+06  
1.00E+07  
1.00E+08  
Offset Frequency (Hz)  
Blue = RF Generator  
Green = Si5326  
Red = Si5324  
Figure 94. RF Generator, Si5326, Si5324 (10 kHz Jitter)  
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APPENDIX I—Si5374 AND Si5375 PCB LAYOUT RECOMMENDATIONS  
The following is a set of recommendations and guidelines for printed circuit board layout with the Si5374 and  
Si5374 devices. Because the four DSPLLs are in close physical and electrical proximity to one another, PCB layout  
is critical to achieving the highest levels of jitter performance. The following images were taken from the Si537x-  
EVB (evaluation board) layout. For more details about this board, refer to the Si537x-EVB Evaluation Board User's  
Guide.  
Isolated Vdd’s  
Main Vdd  
Isolated Vdd’s  
The four Vdd supplies shouldbe isolatedfromone another with four ferrite beads. They shouldbe  
separately bypassed with capacitors that are locatedvery close tothe Si537x device.  
Figure 95. Vdd Plane  
Use a solid and undisturbed ground plane for the Si537x and all of the clock input and output return paths.  
For applications that wish to logically connect the four RSTL_x signals, do not tie them together underneath the  
BGA package. Instead connect them outside of the BGA footprint.  
Where possible, place the CKOUT and CKIN signals on separate PCB layers with a ground layer between  
them. The use of ground guard traces between all clock inputs and outputs is recommended.  
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These four resistors forcethe common RESET connection away from the BGA footprint  
Figure 96. Ground Plane and Reset  
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The following is a set of recommendations and guidelines for printed circuit board layout with the Si5374 and  
Si5374 devices. Because the four DSPLLs are in close physical and electrical proximity to one another, PCB layout  
is critical to achieving the highest levels of jitter performance. The following images were taken from the Si537x-  
EVB (evaluation board) layout. For more details about this board, please refer to the Si537x-EVB Evaluation Board  
User's Guide.  
As much as is possible,do not route clock input and outputsignals  
underneaththe BGApackage. The clock outputsignals should go  
directlyoutwards from the BGA footprint.  
Figure 97. Output Clock Routing  
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OSC_P,  
OSC_N  
Avoidplacing the OCS_P and OSC_N signals on the same layer as the clock outputs. Add  
grounded guard traces surrounding the OSC_Pand OSC_N signals.  
Figure 98. OSC_P, OSC_N Routing  
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APPENDIX J—Si5374 AND Si5375 CROSSTALK  
While the four DSPLLs of the Si5374 and Si5375 are in close physical and electrical proximity to one another,  
crosstalk interference between the DSPLLs is minimal. The following measurements show typical performance  
levels that can be expected for the Si5374 and Si5375 when all four of their DSPLLs are operating at frequencies  
that are close in value to one another, but not exactly the same.  
Si5374, Si5375 Crosstalk Test Bed  
All four DSPLLs share the same frequency plan:  
38.88 MHz input.  
38.88 MHz x 4080 / 227 = 698.81 MHz output (rounded).  
There are four slightly different input frequencies:  
DSPLL A: 38.88 MHz + 0 ppm => 38.88000000 MHz  
DSPLL B: 38.88 MHz + 1 ppm => 38.88003888 MHz  
DSPLL C: 38.88 MHz + 10 ppm => 38.88038880 MHz  
DSPLL D: 38.88 MHz + 20 ppm => 38.88077760 MHz  
Table 83. Si5374/75 Crosstalk Jitter Values  
DSPLL  
Jitter, fsec RMS  
A
B
C
D
334  
327  
358  
331  
OSC_P, OSC_N Reference:  
Si530 at 121.109 MHz  
Test equipment:  
Agilent E5052B  
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Figure 99. Si5374, Si5375 DSPLL A  
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Figure 100. Si5374, Si5375 DSPLL B  
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Figure 101. Si5374, Si5375 DSPLL C  
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Figure 102. Si5374, Si5375 DSPLL D  
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DOCUMENT CHANGE LIST  
Revision 0.3 to Revision 0.4  
Updated AC Specifications in Table 8, “AC  
Added Si5365, Si5366, Si5367, and Si5368  
operation at 3.3 V  
Added input clock control diagrams in Section “7.4.  
Added new crystals into Table 59, “Approved  
Revision 0.4 to Revision 0.41  
Added Si5324.  
Revision 0.41 to Revision 0.42  
Moved Si5326 specifications to the Si5326 data  
sheet.  
Revision 0.42 to Revision 0.5  
Added Si5327, Si5369, Si5374, and Si5375.  
Removed Si5319 and Si5323 from the spec tables.  
Updated the typical phase noise plots.  
Added new appendixes G, H, I, and J.  
Updated spec table values.  
Added examples and diagrams throughout.  
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NOTES:  
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CONTACT INFORMATION  
Silicon Laboratories Inc.  
400 West Cesar Chavez  
Austin, TX 78701  
Tel: 1+(512) 416-8500  
Fax: 1+(512) 416-9669  
Toll Free: 1+(877) 444-3032  
Please visit the Silicon Labs Technical Support web page:  
and register to submit a technical support request.  
The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice.  
Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from  
the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features  
or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, rep-  
resentation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability  
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation conse-  
quential or incidental damages. Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to  
support or sustain life, or for any other application in which the failure of the Silicon Laboratories product could create a situation where per-  
sonal injury or death may occur. Should Buyer purchase or use Silicon Laboratories products for any such unintended or unauthorized ap-  
plication, Buyer shall indemnify and hold Silicon Laboratories harmless against all claims and damages.  
Silicon Laboratories, Silicon Labs, and DSPLL are trademarks of Silicon Laboratories Inc.  
Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders.  
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