Headset Reference Design
nRD24V1
User Guide v1.0
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Reproduction in whole or in part is prohibited without the prior written permission of the copyright holder.
February 2007
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Headset Reference Design v1.0
Contents
1
2
3
3.1
Introduction .................................................................................................4
System Description .....................................................................................5
Hardware description ..................................................................................7
nRD24V1 Radio module ......................................................................7
Audio Codec.....................................................................................7
Micro controller.................................................................................8
Radio circuit .....................................................................................8
Antenna matching network...............................................................8
Power supply....................................................................................8
Programming....................................................................................8
Specifications...................................................................................9
Application board .................................................................................10
Audio interface .................................................................................10
Jumpers ...........................................................................................12
Antenna............................................................................................12
Power supply....................................................................................12
Buttons.............................................................................................13
Programming....................................................................................13
USB dongle..........................................................................................14
USB Interface...................................................................................15
Micro controller.................................................................................15
Radio circuit .....................................................................................15
Power supply....................................................................................15
Programming....................................................................................15
Specifications...................................................................................16
Hardware design guidelines........................................................................17
Headset................................................................................................17
Antenna............................................................................................17
Interfaces .........................................................................................17
Crystals ............................................................................................18
MCU.................................................................................................18
Battery..............................................................................................18
USB dongle..........................................................................................19
Antenna............................................................................................19
MCU.................................................................................................19
Crystals ............................................................................................19
Appendix .....................................................................................................20
Bill Of Materials (BOM) ........................................................................20
Application board schematics ..............................................................23
RF module schematics.........................................................................24
USB dongle schematics.......................................................................25
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
4
4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.2
4.2.1
4.2.2
4.2.3
5
5.1
5.2
5.3
5.4
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User Guide
1
Introduction
This user guide is for the nRD24V1 headset reference design, a voice quality wireless headset for Voice
over IP (VoIP) applications. The quality of the audio in this design is the same as the audio quality in tele-
phony.
This user guide describes the nRD24V1 system, HW modules and gives guidelines on how to take this ref-
erence design and build it into a headset application for a finished product.
The nRD24V1 consists of a USB dongle and two application boards with a radio module mounted. You can
establish a full duplex voice link between one application board and the USB dongle or between the two
application boards.
Target applications for the nRD24V1 are:
•
•
•
Voice over IP headsets
Short range intercom applications
Toys
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Headset Reference Design v1.0
System Description
2
The headset unit can be used to communicate with either a USB dongle or an audio dongle.
Figure 1. ”Headset unit with a USB configuration” and Figure 2. ”System diagram of headset unit with USB
configuration” illustrate the headset unit with a USB configuration.
Headset
unit
USB
dongle
Figure 1. Headset unit with a USB configuration
Application
Voice
Application
Voice
Protocol
Protocol
ShockBurst
ShockBurst
USB
Audio Controller
MCU
MCU
PHY
PHY
I/O
RF
I/O
RF
USB
I/O
I/O
USB
I/O
In/Out
Audio
Out
Audio
DAC
ADC
In
LED
Buttons
LED
Figure 3. ”Headset unit with an audio dongle configuration” and Figure 4. ”System diagram of headset unit
with audio dongle configuration” illustrate the headset unit with audio dongle configuration.
Headset
unit
Audio
dongle
Figure 3. Headset unit with an audio dongle configuration
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Application
Voice
Application
Voice
Protocol
Protocol
ShockBurst
ShockBurst
MCU
MCU
PHY
PHY
I/O
RF
I/O
RF
I/O
I/O
Audio
Out
Audio
Audio
Out
Audio
In
DAC
ADC
DAC
ADC
In
Buttons
LED
LED
Buttons
Figure 4. System diagram of headset unit with audio dongle configuration
The headset unit and the audio dongle are based on the same hardware. Both use an audio codec to pro-
vide coding and decoding of the analog audio signals to 16-bit linear PCM code. This bit stream is pro-
cessed by the micro controller to an 8-bit a-law bit stream, which is sent to the nRF24L01 for wireless
transmission. The nRF24L01 uses the ShockBurst feature to transmit and receive the RF packets in a time
multiplexed scheme. The micro controller fetches received 8-bit a-law samples from the nRF24L01, con-
verts to 16-bit linear PCM, and outputs to the audio codec. Button status is read by the MCU and embed-
ded in the RF packets.
The USB Dongle uses a USB Audio Controller to handle the USB interface. The audio samples are 16 bit
linear PCM between the USB Audio Controller and the micro controller, where the micro controller acts as
a bus master. The audio frame signals are derived from clock output from the USB Audio Controller to
keep the audio frames in sync with the USB audio frames. The micro controller can also access the USB
HID interface through the I2C bus, also with the micro controller as the bus master. The USB HID interface
is used to upstream button status received from the headset to the USB host. The micro controller converts
the 16 bit linear PCM code to an 8-bit a-law bit stream, which is sent to the nRF24L01 for wireless trans-
mission. The nRF24L01 uses the ShockBurst feature to transmit and receive the RF packets in a time mul-
tiplexed scheme.
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3
Hardware description
3.1
nRD24V1 Radio module
The radio module is a complete system for telephone quality wireless headset applications intended for
VoIP. It can be used in a headset, or in an audio module for connection to a PC audio outlet. There are 6
GPIOs for buttons or LEDs on the radio module.
The radio module is mounted on a 25 x 12 x 0.8 mm, 4-layer FR4 circuit board, with components on one
side.
5
1
4
2
3
1
2
3
RF crystal
nRF24L01
MCU
4
5
Audio codec
MCU crystal
Figure 5. nRD24V1 radio module
3.1.1
Audio Codec
The audio codec is a XE3005 from Semtech that receives a 4.096 MHz master clock from the micro con-
troller. The micro controller configures the codec through the SPI interface. The 8 ksps audio samples are
transferred on the I2S interface, where the micro controller is the bus master.
The microphone input has a 1.1 VDC bias for driving the microphone.
The loudspeaker outputs are a differential class D output and need some external filtering components.
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3.1.2
Micro controller
The micro controller is an AVR, ATmega88 and runs on a 4.096 MHz crystal. The micro controller’s main
tasks are:
•
•
•
•
Setting up codec and RF circuits.
Converting 16 bit PCB audio samples from the codec to 8 bit a-law samples to the radio circuit.
Converting 8-bit a-law samples from the radio circuit to 16-bit linear PCM.
Handling the RF protocol.
Additionally, five button inputs are scanned and one output is provided for driving. For example, this can be
used for an LED.
3.1.3
Radio circuit
The radio circuit (nRF24L01) is a complete radio transceiver for use in the unlicensed 2.4 GHz band. A 16
MHz crystal is used as a frequency reference for the RF. The RF output is matched to approximately 50
ohm at the antenna port. See section 3.1.4 ”Antenna matching network” below.
3.1.4
Antenna matching network
The RF output of the radio module is matched to approximately 50 ohm. An antenna is needed to set up
the RF link. There is a variety of different antenna types, please see section 4.1.1 ”Antenna” for more infor-
mation.
3.1.5
Power supply
The module needs a power supply in the range of 1.9 to 3.3 Volts. The module has been tested with a sup-
ply consisting of two ZinkAir cells (type 675) in series. Check the current consumption values shown in
Table 1. ”Electrical Specifications” below.
Note: Not all battery types are capable of handling the peak and average currents, even if the bat-
tery capacity is sufficient.
3.1.6
Programming
The module can be programmed using the ISP connector on the application board (see section 3.2 ”Appli-
cation board”), by connecting the appropriate pins on the module, or by using test probes on the corre-
sponding exposed vias on the back of the board.
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3.1.7
Specifications
Operating conditions
Status
Value
Supply voltage
1.9 - 3.6 V
Current consumption
Idle
Connected
< 1 mA average (15 mA peak) at 2.5 V supply
< 7 mA average (15 mA peak) at 2.5 V supply
2402-2478 MHz
Radio frequency
Output power
0 dBm
Table 1. Electrical Specifications
PCB attributes
Description
PCB type
PCB dimension (length x width x height)
0.8 mm 4 layer FR4
25 mm x 12 mm x 0.8 mm
Table 2. Physical Specifications
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3.2
Application board
The nRF24L01-VHR1 application board contains all peripherals necessary to build a complete audio mod-
ule from the nRF24L01-VHR1 radio module.
6
7
1
2
8
9
3
4
10
11
5
1
2
3
4
5
6
Radio module
Linear regulator
Jumpers
Audio interface
Jumpers
7
8
9
P3 external power
Batteries
Switches 7 and 8
10 ISP programming
11 Buttons
Switch 6
Figure 6. Application board components
3.2.1
Audio interface
This module can be used to set up a wireless audio link, for example, from a PC to a headset. The radio
module is the same for both sides of the link, but needs some external components to interface with either
the PC audio connections, or a microphone/loudspeaker for a headset.
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3.2.1.1
Headset interface
The loudspeaker(s) are driven differentially, and need some filtering due to the class D output amplifier of
the audio codec. Figure 7. ”Loudspeaker interface” shows a typical filter network that can be used for driv-
ing a headset loudspeaker. The filter depends on the chosen loudspeaker.
The microphone can be connected directly to the codec input. The codec input has a 1.1 V supply that can
power a typical headset microphone.
100p
C1
R1
56
L1
470u
AOUTP
AOUTN
C2
4.7u
C3
4.7u
L2
470u
56
R2
C4
100p
Figure 7. Loudspeaker interface
3.2.1.2
PC interface
The differential loudspeaker output from the codec must be connected single ended to the PC microphone
input and the PC loudspeaker output must be connected to the codec microphone input to interface with a
PC audio port. Figure 8. ”PC input interface” shows the networks that accommodate this. The loudspeaker
output from the PC must be level adjusted and a network as shown in Figure 9. ”PC output interface” used.
R3
1k
C5
10n
C6
10u
R4
22k
R5
22k
100p
C1
R1
56
L1
470u
AOUTP
AOUTN
U1
5
C8
2.2u
R6
22k
R7
C7
100n
4.7k
V+
4
3
-
PC microphone input
1
C2
4.7u
C3
4.7u
L2
470u
+
V-
4.7k
R8
2.2u
C9
LM7301
2
56
R2
R9
22k
C4
100p
Figure 8. PC input interface
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C1
R1
1k
C2
PC loudspeaker out
AIN
2.2u
2.2u
R2
47
Figure 9. PC output interface
3.2.2
Jumpers
The application board can be set up to interface a headset microphone and loudspeaker, or a PC audio
outlet by placing the jumpers as shown in Table 3. ”Audio filter settings” below. The filter components
mounted should be appropriate for most headset loudspeakers.
CJ2
Connect to headset Connect to headset Mount jumpers 4 Mount jumper 2.
microphone. loudspeaker and 5
CJ3
W1
W2
Connecting to
headset
Connecting to PC Connect to PC micro- Connect to PC loud- Mount jumpers 1, Mount jumper 1.
phone input speaker output 2 and 3
Table 3. Audio filter settings
3.2.3
Antenna
The RF output of the radio module is matched to approximately 50 ohm. An antenna must be connected to
the SMA connector to set up an RF link.
3.2.4
Power supply
The application board is fitted with two coin-cell battery holders, connected in series, for use with ZinkAir
(type 675) batteries. The board also contains a footprint for a CR2 Li battery holder (1/2 AA, Bulgin
BX0031). Alternatively, an external power supply can be connected to P3. You select battery or external
voltage with SW6.
The voltage supply to the RF module should be between 1.9 and 3.6 V. If the onboard 2.5 V linear regula-
tor is used, the input voltage should be between 3 and 15 V. The linear regulator can be switched on or
bypassed with SW7 and SW8 (both switches should have the same position).
Note: Do not exceed 3.6 V when using external voltage unless the linear regulator is used, as this
can damage the radio module.
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3.2.5
Buttons
There are five buttons on the application board and these are connected to the AVR micro controller on the
radio module as shown in Figure 10. ”Button mapping”.
SW1
AVR pin 23
SW2
SW3
SW4
AVR pin 24
AVR pin 25
AVR pin 26
SW2
AVR pin 27
Figure 10. Button mapping
3.2.6
Programming
The radio module can be programmed through the 6-pin ISP connector (P1) with an AVR programming
tool like the STK500 from Atmel. The programming procedure is as follows:
1.
If the unit has never been programmed, set the AVR fuses:
• Preserve EEPROM memory through chip erase cycle; [EESAVE = 0]
• Brown-out detection level at Vcc=1.8V; [BODLEVEL=110]
• Clock output on PORTB0; [CKOUT=0]
• Ext.Crystal Osc. Frequency 3.0 - 8.0MHz; [CKSEL=1101 SUT=11]
Write the SW hex file into the AVR program memory.
Write a 3-byte ID into the AVR EEprom. The address should be written with the MSB at address
00.
2.
3.
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3.3
USB dongle
The USB dongle establishes a wireless audio link with the radio module in a headset and is identified as an
audio device in the PC operating system.
The USB dongle is mounted on a 0.8 mm, 4-layer FR4 circuit board, with components on both sides of the
board.
3
2
1
4
1
2
MCU
MCU crystal
3
4
nRF24L01
RF crystal
Figure 11. nRD24V1 USB dongle top side
2
1
3
1
2
USB MCU
EE Prom
3
ISP connector
Figure 12. nRD24V1 USB dongle bottom side
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3.3.1
USB Interface
The USB interface is handled by the Sonix SN11220 USB Audio Controller. All the USB communications
are handled by the SN11220. The audio samples are 16 bit linear PCM on the I2S port, where the micro
controller acts as a bus master (PADFUN mode 4’1100 in the SN11220ACF data sheet). The audio frame
signals are derived from the 2.048 MHz clock output from the USB controller. This synchronizes the audio
frames with the USB audio frames. The micro controller can also access the USB HID interface through
the I2C bus, also with the micro controller as the bus master.
3.3.2
Micro controller
The micro controller is an AVR, ATmega88 that runs on a 6.00 MHz crystal. The micro controller’s main
tasks are:
•
•
Setting up USB controller and radio circuits.
Converting 16 bit PCM audio samples from the USB controller to 8 bit a-law samples for the radio
circuit.
•
•
•
Converting 8-bit a-law samples from the radio circuit to 16-bit linear PCM.
Handling the RF protocol.
Optional HID interface for communication with PC application.
In addition, an LED output is available. The LED will light up when USB audio activity is present on the
USB port.
3.3.3
Radio circuit
The radio circuit (nRF24L01) is a complete radio transceiver for use in the unlicensed 2.4 GHz band. A 16
MHz crystal is used as frequency reference for the RF and an antenna is included in the layout.
3.3.4
Power supply
The USB dongle is powered from the USB port and needs no extra supply.
3.3.5
Programming
A 6-pin ISP connector is available on the back of the PCB. The included ISP cable can be used to connect
this connector to an AVR programming tool like the STK500 from Atmel.The programming procedure is as
follows:
1.
If the unit has never been programmed, set the AVR fuses:
• Preserve EEPROM memory through chip erase cycle; [EESAVE = 0]
• Brown-out detection level at Vcc=2.7V; [BODLEVEL=101]
• Ext. Full-swing Crystal; [CKSEL=0111 SUT=01]
2.
3.
Write the SW hex file into the AVR program memory.
Write a 3-byte ID into the AVR EEprom. The address should be written with the MSB at address
00.
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3.3.6
Specifications
Operating conditions
Status
Value
Supply voltage
Current consumption
4.5 - 5.5 V
< 24 mA
< 28 mA
Idle
Connected
Radio frequency
Output power
2402-2478 MHz
0 dBm
Table 4. Electrical Specifications
PCB attributes
Description
PCB type
0.8mm 4 layer FR4
PCB dimension (length x width x height)
42mm x 16mm x 0.8mm
Table 5. Physical Specifications
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Hardware design guidelines
4
This chapter describes important issues that might affect you when developing the headset reference
design for a finished product. The USB dongle can be used as-is, but the headset must be redesigned to fit
into a headset for a finished product. However, the radio module mounted on the headset can be used as-
is together with the audio interfaces from the application board.
Note: Most radio regulations do not allow more than 0dBm output power without doing proper fre-
quency hopping. Adding a PA to this design requires a major re-design of the radio protocol
because the headset reference design uses a frequency agility protocol.
4.1
Headset
The radio module is used as-is in the headset design, but it must be interfaced in a way that ensures opti-
mal performance.
4.1.1
Antenna
The radio module is connected to the antenna on the application board. This antenna does not fit into a
headset design for a finished product, so using the radio module in a headset application for a finished
product will require a different type of antenna.
In a headset application for a finished product, the radio module must be mounted on a PCB with an
antenna terminal. On this antenna terminal, any 50 ohm 2.4GHz antenna can be used, from an inexpen-
sive PCB antenna to space saving chip antennas.
There are different types of PCB antennas, from inverted F antennas to simple quarter wave antennas.
You must know the characteristics of the chosen antenna and implement it as required. Tuning the
antenna will be necessary because an antennas impedance and performance is affected by the environ-
ment the antenna is used in.
Using a chip antenna must only be done according to the chip antenna vendors recommendations.
The radio module is equipped with the recommended antenna matching network layout for the nRF24L01.
When operating from the application board, the radio module’s antenna matching network is tuned to
match the application board antenna impedance.
When using the radio module in a headset application for a finished product it is important to tune the
antenna matching network to match the impedance at the antenna’s terminal. Another important task of
the antenna matching network is to suppress spurious energy. You can achieve this by following our white
4.1.2
Interfaces
4.1.2.1
Buttons
Any active closed push buttons referring to ground can be used because the MCU used on the radio mod-
ule has internal pull-up resistors on the button input signals. The radio module can handle up to five but-
tons.
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4.1.2.2
Audio interface
The audio interfaces from the application board should be used when using the radio module as-is in a
design. The audio interfaces are matched to the used audio codec on the radio module. Using a different
codec or load on the interfaces requires redesign of the audio interfaces.
4.1.3
Crystals
The crystal used as the RF crystal is a 16 MHz crystal. Any replacement of this crystal must fulfill the crys-
tal requirements found in the nRF24L01 Product Specification.
The MCU crystal fulfills the requirements given by the MCU. The frequency must be 4.096MHz in order to
get the timing correct. Any replacements must follow these requirements.
4.1.4
MCU
It is important that the MCU has a double buffered SPI in both the TX and RX direction because the MCU
handles the audio stream and requires it to be continuous.
A replacement of the MCU must fulfill these requirements:
•
•
•
•
•
•
•
•
•
•
•
•
8-bit MCU
4.096 MHz clock frequency
1 to 2 cycles per instruction
4bytes E2PROM Memory (can be external)
1kbyte of IRAM (can maybe work with 512kbytes)
8kbyte program memory (possible to get down to 5 to 6kbytes)
One Double buffered, synchronous hardware SPI both on RX and TX -or- Ideally I2S interface
One SPI port for RF and codec
Watchdog times for power management
One 16-bit timer (Master sync clock)
One 8-bit timer (hardware sync clock)
1.9 to 3.6V supply voltage
4.1.5
Battery
The batteries included in the reference design kit are of the type Zink-Air (Zn), size 675. Two batteries of
this size are connected in series to achieve the supply voltage needed.
Any battery that can supply a voltage between 1.9V and 3.6V and sustain the peak current of 15mA can be
used in this application.
You can calculate the battery lifetime in both “talk time” and “standby time” from the average current con-
sumption. At Vdd=3V the average current consumption in connect mode is 7mA and the average current
consumption in idle mode is 250µA. (At Vdd=2V they are 5.7V and 230µA, respectively.) A battery with
capacity 630mAh, like the Zn 675, will have the following battery lifetime:
•
•
Talk time: 630mAh/7mA = 90h.
Standby time: 630mAh/250µA=2520h.
The figures for Vdd=3V are used because the two batteries in series have a nominal output voltage of
2.8V.
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4.2
USB dongle
4.2.1
Antenna
The USB Dongle uses a PCB quarter wave antenna. The USB Dongle is production ready, and any modi-
fications to the antenna are only required as part of the antenna tuning process to compensate for plastic
housing, and so on.
If you want an antenna redesign, any 50 ohm 2.4GHz antenna can be used, from an inexpensive PCB
antenna to space saving chip antennas.
There are different types of PCB antennas, from inverted F antennas to simple quarter wave antennas.
You must know the characteristics of the chosen antenna and implement it as required. Tuning the
antenna will be necessary because an antenna’s impedance and performance are affected by the environ-
ment the antenna is used in.
Using a chip antenna must only be done according to the chip antenna vendors recommendations.
The USB Dongle is equipped with the recommended antenna matching network layout for the nRF24L01
and a PCB quarter wave antenna. If a different antenna is going to be used it is important to tune the
antenna matching network to match the impedance at the antenna’s terminal. Another important task of
the antenna matching network is to suppress spurious energy. This can be achieved by following our White
4.2.2
MCU
A replacement of the MCU must fulfill these requirements:
•
•
•
•
•
•
•
•
•
•
•
•
•
8-bit MCU
6 MHz clock frequency
1 to 2 cycles per instruction
4bytes E2PROM Memory (can be external)
1kbyte of IRAM (can maybe work with 512kbytes)
8kbyte program memory (possible to get down to 5 to 6kbytes)
One Double buffered, synchronous hardware SPI both on RX and TX -or- Ideally I2S interface
One SPI port for RF and codec
One two wire interface to USB Audio Controller for call control (open drain type)
Watchdog times for power management
One 16-bit timer (Master sync clock)
One 8-bit timer (hardware sync clock)
1.9 to 3.6V supply voltage
4.2.3
Crystals
The crystal used as the RF crystal is a 16 MHz crystal. Any replacement of this crystal must fulfill the crys-
tal requirements found in the nRF24L01 Product Specification.
The MCU crystal fulfills the requirements given by the MCU. The frequency must be 6.0 MHz in order to
get the timing correct. Any replacements must follow these requirements.
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5
Appendix
5.1
Bill Of Materials (BOM)
Part
Designator
Footprint
SM/0805
Description
10u
10n
C1 C3 C22 C27
C2 C4 C23
C11 C14
C16 C17
C20 C21 C25 C26
C24
Capacitor 0805/X5R/6V3/15%
Capacitor 0603/X7R/50V/10%
Capacitor 0603/X5R/6.3V/10%
Capacitor 0603/NP0/50V/5%
Capacitor 0603/X5R/6.3V/10%
Capacitor 0603/X7R/16V/10%
Coax connector 85 SMA-50-0-
101
SM/0603
SM/0603
SM/0603
SM/0603
SM/0603
TH/SMA
4.7u
100p
2.2u
100n
SMA
CJ1
3.5mm
R
470u
CJ2 CJ3
D1
L1 L5
TH/CON/KLBR4
0603_D
SM/1210
Audio Jack, 3.5mm KLBR 4
LED, Red EL19-21VRC
Inductor, Power
LQH32MN471J23L
6PIN2ROW
PH2
nRF24L01 VoIP Appli- PCB1
cation Board
P1
P3
6PIN/2ROW
Pin row 825457-3
PHOENIX/2.54/2P Connector, screw MPT0.5/2-2.54
PCB
BC847BL
Q1
R3
R4 R5
R6 R7
R8 R9 R12
R13 R16 R17 R18
R25
SM/SOT23
SM/0603
SM/0603
SM/0603
SM/0603
SM/0603
NPN BC847BL
470
100k
56
0
1k
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
47
220
22k
4.7k
SW6x6
R14
R15
SM/0603
SM/0603
SM/0603
SM/0603
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Resistor, 0.1W 0603/1%
Switch, TACT B3S1000
R19 R20 R21 R24
R22 R23
SW1 SW2 SW3 SW4 SM/SW/6x6
SW5
SPDT
SW6 SW7 SW8
TH/SW/OS1020
Switch, Mechanical
OS102011MS2QN1
Radio Module nRF24L01-VHR1-
RM
Linear Regulator LP2985AIM5-
2.5
nRF24L01-VHR1-RM U1
WHS-nRF24L01
SM/SOT23-5
LP2985AIM5-2.5
U2
12MM
LM7301
U3 U5
U6
BAT/12MM
SM/SOT23-5
Battery holder 12 mm 501
OpAmp LM7301IM5
5LUS
W1
10PIN/2ROW/LUS Pin Row 825457-5
2LUS
Jumper 2.54 mm
W2
4PIN/2ROW/LUS
Pin row 825457-2
Jumper, 2.54mm M7565-05
Rubber Feet
WJ1 WJ2 WJ3 WJ4
One in each corner
under the board
Table 6. Application board BOM
Revision 1.0
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Headset Reference Design v1.0
Part
Designator
Footprint
Description
10n
10u
1.0n
33n
4.7p
2.2n
4.7p
1.0p
15p
22p
47u
C1 C3 C4 C5 C6 C11 SM/0402
Capacitor 0402/X7R/16V/10%
Capacitor 0805/X5R/6V3/15%
Capacitor 0402/X7R/50V/10%
Capacitor 0402/X7R/16V/10%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/X7R/50V/10%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/NP0/50V/5%
Capacitor,Tant, B
C2 C13 C22
C7
SM/0805
SM/0402
C8
SM/0402
C9
SM/0402
C10
SM/0402
C12
SM/0402
C14 C26
C15 C16
C17 C18
C23
SM/0402
SM/0402
SM/0402
CAPMP3528X210L
TAJB476K004R
470n
2.2u
G
C24
C25
D1
SM/0402
SM/0603
0603_D
Capacitor 0402/X5R/6.3V/10%
Capacitor 0603/X5R/6.3V/10%
LED, Green EL19-21UGC
Inductor, RF
4.7n
L1
SM/0402
LQP15MN4N7B02D
8.2n
5.6n
L2
L3
P1
SM/0402
Inductor, RF
LQP15MN8N2B02D
Inductor, RF
LQP15MN5N6B02D
USB connector 48037-2100
PCB
SM/0402
USB-A
CON/USB-A/PLUG
nRF24L01 VoIP USB PCB1
Dongle Board
PDTC115TU
Q1
SM/SOT323
NPN with resistors
PDTC115TU
22k
22
1M
100K
0
10
2.2k
3.3k
470
R1
R2 R3
R4
R5
R8 R9 R21 R26
R10
R11
R12
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
R20
R23 R24
R25
10k
1.5k
SN11220ACF
U1
TSQFP50P900X900X16 USB Audio Controller
0-48L
SN11220ACF
nRF24L01
ATMega88
U2
U3
QFN20-4x4
QFN50P500X500X100-
33AL
RF Transceiver nRF24L01
Microcontroller ATmega88V-
10MU
93C46
U4
EEPROM, 1k AT93C46-10TU-
2.7
TSSOP-8
16MHz
6.0MHz
Connector
Y1
Y2
P3
Crystal TSX-10 16MHz
Crystal CA-301 6.000M-C
ISP Connector BM06B-SRSS-
TB(LF)(SN)
XW4*2.5
TH/XO/CA-301
0
Table 7. USB dongle BOM
Revision 1.0
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User Guide
Part
Designator
C1 C13
C2 C5
C3 C4
C6
Footprint
SM/0402
Description
100n
22p
15p
4.7p
2.2n
1.0p
10n
1u
33n
1.0n
0.8p
4.7n
8.2n
4.7n
Capacitor 0402/X7R/16V/10%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/X7R/50V/10%
Capacitor 0402/NP0/50V/5%
Capacitor 0402/X7R/16V/10%
Capacitor 0402/X5R/6.3V/10%
Capacitor 0402/X7R/16V/10%
Capacitor 0402/X7R/50V/10%
Capacitor 0402/NP0/50V/5%
Inductor, RF LQP15MN4N7B02D
Inductor, RF LQP15MN8N2B02D
Inductor, RF LQP15MN4N7B02D
PCB
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
C7
C9
C10 C14 C16
C11 C12
C15
C17
C18
L1
L2
L3
nRF24L01 VoIP PCB1
RF Module Board
10
100k
1M
390k
22k
R1 R3
R2 R9
R4
R5
R8
SM/0402
SM/0402
SM/0402
SM/0402
SM/0402
TSSOP-20
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Resistor, 0.1W 0402/1%
Audio Codec XE3005I033TRLF
XE3005
ATMega88
U1
U3
QFN50P500X500X Microcontroller ATmega88V-
100-33AL
10MU
nRF24L01
4.096MHz
U4
Y1
QFN20-4X4
TH/XO/CA-301
RF Transceiver nRF24L01
Crystal CSA309-4.096MABJ-UB
16MHz
Y2
XW4*2.5
Crystal TSX-10 16MHz
Table 8. Radio module BOM
Revision 1.0
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Headset Reference Design v1.0
5.2 Application board schematics
Revision 1.0
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User Guide
5.3
RF module schematics
33
21
5
3
GND
GND
GND
GND
18
6
4
AVCC
VCC
VCC
8
14
17
20
VSS
VSS
VSS
VSS
15
7
18
VDD
VDD
VDD
Revision 1.0
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Headset Reference Design v1.0
5.4
USB dongle schematics
36
35
VDD5D
23
48
37
12
VSSA_PLLA
VSSA_PLLB
VSS
VDDOUT
7
21
46
VDD
VDD
VDD
9
TAVSS
TAVDD
33
21
5
3
GND
18
6
4
GND
GND
GND
AVCC
VCC
VCC
8
14
17
20
VSS
VSS
VSS
VSS
15
7
18
VDD
VDD
VDD
1
1
Revision 1.0
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