4x4 Crosspoint Switch EVM
User's Guide
January 2004
HPL-D
SLLU064A
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EVM IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR
EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the
goods being provided may not be complete in terms of required design–, marketing–, and/or manufacturing–
related protective considerations, including product safety measures typically found in the end product
incorporating the goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may not meet the technical requirements of the
directive.
Should this evaluation kit not meet the specifications indicated in the EVM User’s Guide, the kit may be
returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE
EXCLUSIVE WARRANTY MADE BY SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user
indemnifies TI from all claims arising from the handling or use of the goods. Please be aware that the
products received may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). Due to the open
construction of the product, it is the user’s responsibility to take any and all appropriate precautions with
regard to electrostatic discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE
LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is
not exclusive.
TI assumes no liability for applications assistance, customer product design, software performance,
or infringement of patents or services described herein.
Please read the EVM User’s Guide and, specifically, the EVM Warnings and Restrictions notice in the EVM
User’s Guide prior to handling the product. This notice contains important safety information about
temperatures and voltages. For further safety concerns, please contact the TI application engineer.
Persons handling the product must have electronics training and observe good laboratory practice standards.
No license is granted under any patent right or other intellectual property right of TI covering or relating to any
machine, process, or combination in which such TI products or services might be or are used.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2003 - 2004, Texas Instruments Incorporated
3
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EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage range of -0.7 V to 4 V and the output voltage range
of -0.5 V to 4 V.
Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the
EVM. If there are questions concerning the input range, please contact a TI field representative prior to
connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible
permanent damage to the EVM. Please consult the EVM User’s Guide prior to connecting any load to the
EVM output. If there is uncertainty as to the load specification, please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than 60°C. The
EVM is designed to operate properly with certain components above 60°C as long as the input and output
ranges are maintained. These components include but are not limited to linear regulators, switching
transistors, pass transistors, and current sense resistors. These types of devices can be identified using the
EVM schematic located in the EVM User’s Guide. When placing measurement probes near these devices
during operation, please be aware that these devices may be very warm to the touch.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2003 - 2004, Texas Instruments Incorporated
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Preface
Read This First
About This Manual
This evaluation module (EVM) user’s guide describes the hardware, theory
of operation, and use of the EVM for evaluating the high-speed
performance and functionality of either the SN65LVDS125A or
SN65LVDS250 4x4 crosspoint switches.
How to Use This Manual
Chapter 1 provides an overview of the functional configurations and signal
paths. Typical hardware setup and results are discussed in Chapter 2.
Chapter 3 provides schematics, the board layout, the board layers,
fabrication notes, and bill of materials
Related Documentation from Texas Instruments
SN65LVDS125A, 4x4 1.5 Gbps LVDS Crosspoint Switch Data Sheet
(SLLS595).
SN65LVDS250, 4x4 2.5 Gbps LVDS Crosspoint Switch Data Sheet
(SLLS594).
If You Need Assistance
E-mail technical support http://www-
k.ext.ti.com/sc/technical_support/email_tech_support.asp
Product Information Centers:
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Hong Kong 800-96-5941
Indonesia 001-803-8861-1006
Israel (English) 1800 949 0107 (free phone)
Italy 800 79 11 37 (free phone)
Japan 0120-81-0036
iii
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FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to
subpart J of part 15 of FCC rules, which are designed to provide
reasonable protection against radio frequency interference. Operation of
this equipment in other environments may cause interference with radio
communications, in which case the user at his expense will be required to
take whatever measures may be required to correct this interference.
If your book does not discuss a product that creates radio frequency
interference, delete this section from your preface. If your book does
discuss a product that creates radio frequency interference, you must
include this warning as it appears above.
iv
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Contents
Read This First ................................................................................................................iii
About This Manual..................................................................................................... iii
How to Use This Manual ........................................................................................... iii
Related Documentation from Texas Instruments....................................................... iii
If You Need Assistance ............................................................................................. iii
FCC Warning............................................................................................................. iv
Contents ...........................................................................................................................v
Figures..............................................................................................................................v
Tables ..............................................................................................................................vi
1 Overview....................................................................................................................1-1
1.1 Sample Functional Configurations ...................................................................1-2
1.2 Signal Paths ....................................................................................................1-4
2 Setup and Required Equipment ...............................................................................2-1
2.1 Applying an Input.............................................................................................2-1
2.2 Observing an Output........................................................................................2-4
2.3 Typical Test Results ........................................................................................2-4
3 EVM Construction.....................................................................................................3-1
3.1 Schematic........................................................................................................3-2
3.2 Board Layout Patterns.....................................................................................3-3
3.3 PCB Fabrication Requirements and Stack Up .................................................3-8
3.4 Bill of Materials ................................................................................................3-9
Figures
Figure 1-1. Sample Functional Configurations of the 4x4 Crosspoint Switch..........1-2
Figure 1-2. 4x4 Crosspoint Switch EVM ......................................................................1-3
Figure 1-3. 4x4 Crosspoint Switch Signal Paths.........................................................1-4
Figure 2-1. EVM Power Connections for Either SN65LVDS125A or SN65LVDS250
Evaluation..............................................................................................................2-2
Figure 2-2. Termination for Interfacing LVDS, CML, or LVPECL Drivers ..................2-3
Figure 2-3. Typical Test Results...................................................................................2-5
Figure 3-1. 4x4 Crosspoint Switch EVM Schematic....................................................3-2
Figure 3-2. 4x4 Crosspoint Switch EVM Board Layout...............................................3-3
Figure 3-3. Layer 1–Signal Plane .................................................................................3-4
Figure 3-4. GND Plane...................................................................................................3-5
Figure 3-5. Layer 3–Vcc ................................................................................................3-5
v
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Tables
Figure 3-6. Layer 4–Vcc01 Plane..................................................................................3-6
Figure 3-7. Layer 5–GND Plane ....................................................................................3-6
Figure 3-8. Layer 6–GND/Signal Plane.........................................................................3-7
Tables
Table 2-1 Crosspoint Function Table...........................................................................2-3
Table 3-2. Bill of Materials for the SN65LVDS125A / SN65LVDS250..........................3-9
vi
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Chapter 1
1 Overview
This chapter provides a high-level description of the 4x4 crosspoint switch
EVM mounted with either a SN65LVDS125A, 4x4 1.5-Gbps or a
SN65LVDS250, 4x4 2.5-Gbps crosspoint switch.
Topic
Page
1-2
1.1 Sample Functional Configurations
1.2 Signal Paths
1-4
1-1
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1 Overview
1.1 Sample Functional Configurations
The 4x4 crosspoint switch is a fully non-blocking switch that provides
flexibility in switch configuration for the desired application.
A sample of various functions for which the EVMs can be configured is
shown in Figure 1-1.
C onfigura tion E x a m ple s
S 1 0
0
S 1 1
0
S 2 0
0
S 2 1
1
S 1 0
0
S 1 1
0
S 2 0
0
S 2 1
0
S 3 0
1
S 3 1
0
S 4 0
1
S 4 1
1
S 3 0
0
S 3 1
0
S 4 0
0
S 4 1
0
1Y
1Z
1 Y
1 Z
1 A
1 B
1 A
1 B
2 Y
2 Z
2Y
2Z
2 A
2 B
3 Y
3 Z
3Y
3Z
3 A
3 B
4Y
4Z
4 Y
4 Z
4A
4B
S 1 0
0
S 3 0
1
S 1 1
0
S 3 1
0
S 2 0
0
S 2 1
0
S 4 1
0
S 1 0
S 1 1
S 2 0
1
S 2 1
1
S 3 0
0
1
S 3 1
0
1
S 4 1
0
S 4 0
1
S 4 0
0
1Y
1Z
1A
1B
1 Y
1 Z
1A
1B
2 Y
2 Z
2Y
2Z
3 Y
3 Z
3Y
3Z
3 A
3 B
4 Y
4 Z
4 Y
4 Z
4A
4B
Figure 1-1. Sample Functional Configurations of the 4x4 Crosspoint Switch
1-2
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1 Overview
Figure 1-2 shows the 4x4 crosspoint switch EVM (part number
SN65LVDS125A or SN65LVDS250). The EVM comes with either the
SN65LVDS125A or SN65LVDS250 installed and a copy of the data sheet.
A/W # 6456526
SN65LVDS125A
SN65LVDS250
4X4 Crosspoint Switch EVM
Figure 1-2. 4x4 Crosspoint Switch EVM
1-3
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1 Overview
1.2 Signal Paths
The signal paths on this EVM (see Figure 1-3) include:
Sixteen edge-launch SMA connectors (J1–J16) for high-speed data transmission
❏
❏
❏
❏
Eight jumpers (W1– W8) for active switch logic control
Four jumpers (W9–W12) for enabling and disabling the outputs
Three banana jacks (J17, J18, J19) for power and ground connections. Banana jack J20 is
used for non-LVDS type configurations.
J11
J14
J13
J12
VCC
3DE
J10
VCC
1DE
VCC
2DE
J15
J19
W10
W12
W11
VCC
4DE
VCC01
J9
J16
W9
J18
J20
U1
1
GND
W1
VTERM
W2
W7
W8
J1
VCC
VCC
S11
VCC
S40
VCC
S10
J17
S41
J8
J7
W3
W4
W5
W6
VCC
VCC
S20
VCC
S21
VCC
S30
VCC
S31
J2
J3
J4
J5
J6
`
Figure 1-3. 4x4 Crosspoint Switch Signal Paths
1-4
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Chapter 2
2 Setup and Required Equipment
Both the SN65LVDS125A and the SN65LVDS250 LVDS driver output
characteristics are compliant with the requirements of the TIA/EIA-644
standard. LVDS drivers nominally provide a 350-mV differential signal, with
a 1.2-V offset from ground. These levels are attained when driving a 100-Ω
differential line-termination test load. This requirement includes the effects
of up to 32 standard receivers with their ground references offset up to ±1 V
from that of the driver. This common-mode loading limitation of LVDS
drivers affects how the driver’s characteristics are observed with this EVM,
and the test setup that follows in this manual.
By using three power jacks (J17, J18, and J19) and by optionally installing
termination resistors, different methods of probing can be used to evaluate
the device output characteristics. The typical setup for the 4x4 crosspoint
switch EVM is shown in Figure 2-1.
2.1 Applying an Input
While the use of a split power plane allows the EVM to be terminated within
the oscilloscope, offsetting the EVM ground requires the inputs to the
device to also be offset. Figure 2-1 shows how to offset the EVM and the
inputs to the device. Setting power supply 1 to 3.3 V and power supply 2 to
1.2 V causes the voltage swing of the LVDS outputs to be within the limits
of -200 mV to 200 mV instead of the typical 1 V to 1.4 V. This requires the
inputs of the 4x4 crosspoint switch EVM to also be offset by 1.2 V, resulting
in a voltage swing of -200 mV to 200 mV. VTERM, banana jack J20, is
provided for non-LVDS input terminations such as LVPECL, which requires
a termination voltage. When applying an LVDS input, VTERM can be left
open or connected to GND, which is the common-mode voltage when using
the aforementioned –200-mV to 200-mV input swing.
2-1
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2 Setup and Required Equipment
+
3.3V
-
Power Supply #1
Power Supply #2
+
1.2V
-
SCOPE
(internally
terminated
50
Ω
to GND)
DATA, DATA
Amplitude: 400 mV
Offset: 0.0 V
DATA, DATA
Amplitude: 400 mV
Offset: 0.0 V
Figure 2-1. EVM Power Connections for Either SN65LVDS125A or SN65LVDS250
Evaluation.
Many possible configurations for the 4x4 crosspoint switches are made
available. Table 2-1 provides a description of the different functions and
the required selector settings.
2-2
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2 Setup and Required Equipment
Table 2-1 Crosspoint Function Table
Output Channel 1
Output Channel 2
Output Channel 3
Output Channel 4
Control
Pins
Input
Selected
Control
Pins
Input
Selected
Control
Pins
Input
Selected
Control
Pins
Input
Selected
S10 S11 1Y/1Z
S20 S21 2Y/2Z
S30 S31 3Y/3Z
S40 S41 4Y/4Z
0
0
1
1
0
1
0
1
1A/1B
2A/2B
3A/3B
4A/4B
0
0
1
1
0
1
0
1
1A/1B
2A/2B
3A/3B
4A/4B
0
0
1
1
0
1
0
1
1A/1B
2A/2B
3A/3B
4A/4B
0
0
1
1
0
1
0
1
1A/1B
2A/2B
3A/3B
4A/4B
Apply inputs to the SMA connectors J1–J8. The EVM comes with 50-Ω
resistors installed to VTERM, providing a termination scheme easily
adjusted to accommodate LVDS, LVPECL, or CML output structures. (See
Figure 2-2).
Vterm
50 Ω
LVDS,
LVPECL,
A
or CML
SN65LVDS125 Input
Channels 1-4
B
50 Ω
Vterm
Figure 2-2. Termination for Interfacing LVDS, CML, or LVPECL Drivers
2-3
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2 Setup and Required Equipment
2.2 Observing an Output
In order to minimize the parasitic capacitance in high-speed measurements
(probe capacitance), the 4x4 crosspoint switch EVM provides an offset
power plane (layer 5). This power plane allows the user to offset the device
so that the common-mode output is compatible with the 50 ohms to ground
termination within the scope. Terminating the EVM within the scope
eliminates any bandwidth limitations introduced by a probe.
Direct connection to an oscilloscope with 50-Ω internal terminations to
ground is accomplished without requiring installation of resistors R5 – R16
on the EVM. The outputs are available at J9–J16 for direct connection to
oscilloscope inputs. All cabling used to source and measure signals must
be electrically matched in length to prevent any skew between conductors
of the differential inputs.
Referring back to 2-1, power supply 1 is used to provide the required 3.3 V
to the EVM. Power supply 2 is used to offset the EVM ground relative to the
device under test (DUT) ground. With this power scheme, the common-
mode voltage seen by either the SN65LVDS125A or the SN65LVDS250 is
approximately equal to that of the oscilloscope, thus preventing significant
common-mode current flow. Using dual supplies and offsetting the EVM
ground relative to the DUT ground are simply steps required for the test and
evaluation of devices. Actual designs include high-impedance receivers,
which do not require the setup steps outlined above. If the EVM outputs are
to be evaluated with a high-impedance probe, direct probing on the EVM is
supported via installation of a 100-Ω resistor across the solder pads (R5,
R8, R11, and R14).
Note: Power Supply 2
.Power supply 2 must be able to sink current.
2.3 Typical Test Results
Figure 2-3 is a typical result obtained with the EVM setup shown in Figure
2-1. The inputs (J1–J8) were stimulated with a 223–1 PRBS signal at
1.5 Gbps. The input levels for both clock and data were a differential
voltage of 400 mV, with a common-mode voltage of 0 V (referenced to the
ground of the pattern generator).
2-4
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2 Setup and Required Equipment
Figure 2-3. Typical Test Results.
2-5
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2 Setup and Required Equipment
2-6
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EVM Construction
Chapter 3
3 EVM Construction
This chapter presents the schematics, board layouts, fabrication
information, and the bill of materials.
Topic
Page
3-2
3.1 Schematic
3.2 Board Layout Patterns
3.3 PCB Fabrication Requirements and Stack Up
3.4 Bill of Materials
3-3
3-8
3-9
3-1
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3.1 Schematic
Figure 3-1. 4x4 Crosspoint Switch EVM Schematic
3-2
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3 EVM Construction
3.2 Board Layout Patterns
A/W # 6456526
SN65LVDS125A
SN65LVDS250
4X4 Crosspoint Switch EVM
Figure 3-2. 4x4 Crosspoint Switch EVM Board Layout
3-3
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Figure 3-3. Layer 1–Signal Plane
3-4
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3 EVM Construction
Figure 3-4. GND Plane
Figure 3-5. Layer 3–Vcc
3-5
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Figure 3-6. Layer 4–Vcc01 Plane
Figure 3-7. Layer 5–GND Plane
3-6
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3 EVM Construction
Figure 3-8. Layer 6–GND/Signal Plane
3-7
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3.3 PCB Fabrication Requirements and Stack Up
Notes:
1. PWB TO BE FABRICATED TO MEET OR EXCEED IPC-6012,
CLASS 3 STANDARDS AND WORKMANSHIP SHALL
CONFORM TO IPC-A-600, CLASS 3 CURRENT REVISIONS
2. BOARD MATERIAL AND CONSTRUCTION TO BE UL
APPROVED AND MARKED ON THE FINISHED BOARD.
3. LAMINATE MATERIAL:COPPER-CLAD NELCO N4000-13 (DO NOT USE -13SI)
4. COPPER WEIGHT: 1oz FINISHED
Stackup
Signal: Layer 1
5. FINISHED THICKNESS: 0.062" +/- 0.010"
6. MIN PLATING THICKNESS IN THROUGH HOLES: .001"
7. SMOBC / HASL
0.0075"
GND: Layer 2
0.0075"
8. LPI SOLDERMASK BOTH SIDES USING APPROPRIATE
LAYER ARTWORK: COLOR = GREEN
VCC Power: Layer 3
0.062"
9. LPI SILKSCREEN AS REQUIRED: COLOR = WHITE
VCCO1 Power: Layer 4
GND: Layer 5
10. VENDOR INFORMATION TO BE INCORPORATED ON BACK SIDE
WHENEVER POSSIBLE
0.0075"
11. MINIMUM COPPER CONDUCTOR WIDTH IS: 0.009"
MINIMUM CONDUCTOR SPACING IS: 0.006"
0.0075"
SIGNAL/GND: Layer 6
12. NUMBER OF FINISHED LAYERS: 6
13. ALL 8 MIL HOLES TO BE PLUGGED AND COPLANAR TO
SURFACE
14. SPACING BETWEEN LAYERS 1 AND 2 SHOULD BE 0.0075"
SPACING BETWEEN LAYERS 2 AND 3 SHOULD BE 0.0075"
SPACING BETWEEN LAYERS 4 AND 5 SHOULD BE 0.0075"
SPACING BETWEEN LAYERS 5 AND 6 SHOULD BE 0.0075"
3-8
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3 EVM Construction
3.4 Bill of Materials
Table 3-2. Bill of Materials for SN65LVDS125A / SN65LVDS250 EVM
Item
6456526-1
Qty
6456526-2
Qty
6456526-3 Description
Qty
Pattern
Reference
Designator
1
9
9
9
0.001 µF
402
C2, C3, C4, C5, C6,
C7, C8, C9, C10
2
3
4
5
6
7
8
2
1
2
4
2
1
2
2
1
2
4
2
1
2
2
1
2
4
2
1
2
0.01 µF
0.1 µF
603
C13, C18
C21
603
0.1 µF
1206
402
C14, C19
R5, R8, R11, R14
C11, C16
C22
100 Ω (uninstalled)
10 µF
7343
603
1 µF
1 µF
1206
C15, C20
W1, W2, W3, W4,
W5, W6, W7, W8,
W9, W10, W11, W12
9
12
8
12
8
12
8
3 pos jumper
49.9 Ω (uninstalled)
49.9 Ω
10
11
402
R6, R7, R9, R10,
R12, R13, R15, R16
8
8
8
402
R1, R2, R3, R4, R17,
R18, R19, R20
12
13
2
4
2
4
2
4
68 µF
Cap 592D R
C12, C17
Banana jack
J17, J18, J19, J20
SMA END
J1, J2, J3, J4, J5, J6,
J7, J8, J9, J10, J11,
J12, J13, J14, J15,
J16
14
16
16
16
SMA PCB MT MOD
50 Ω
15
16
17
1
0
0
0
1
0
0
0
1
SN65LVDS125A
SN65LVDS250
Special
38-TSSOP
(DBT)
U1
U1
U1
38-TSSOP
(DBT)
38-TSSOP
(DBT)
18
19
4
1
4
1
4
1
Rubber feet
PWB
3/8”
6456526
PWB
3-9
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