UM2742 User manual - STMicroelectronics
Transcript of UM2742 User manual - STMicroelectronics
November 2020 UM2742 Rev 2 1/44
1
UM2742User manual
High-power RFID reader system based on ST25RU3993
Introduction
The ST25RU3993-HPEV is a high-power RAIN® (UHF) RFID reader system based on the integrated reader IC ST25RU3993.
The purpose of ST25RU3993-HPEV is to provide a comprehensive RAIN RFID reader system that allows the user to evaluate the properties and the features of ST25RU3993. To achieve this goal the ST25RU3993-HPEV board, differently from a typical reference design approach, combines a high RF power and a low RF power RFID reader on a single PCB.
Additionally, the ST25RU3993-HPEV board has been outfitted with numerous easy to access test points and measurement possibilities. With minor modification effort it is possible to change the architecture of the reader. For example, it is possible to control the RF circuitry with external MCU or vice versa. Bypassing the external on-board power amplifier or alternate antenna configurations are additional possibilities.
The ST25RU3993-HPEV is controlled by a graphical user interface (GUI) running on a host PC. The corresponding interface is a USB/UART bridge (requires driver installation). The GUI can be found on dedicated pages on www.st.com.
The board supports tuning the radio frequency from 840 to 960 MHz. and provides two SMB (male) antenna connectors that can be controlled via the GUI. To enable scanning for RAIN RFID transponders connect a suitable 50 Ω UHF antenna for the targeted frequency range.
Figure 1. ST25RU3993-HPEV board
www.st.com
Contents UM2742
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Contents
1 Standard connection setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Board features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1 RF circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Microcontroller and connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 Firmware programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4 Boot mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.6 Test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.6.1 Analog test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.6.2 Digital test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.6.3 Probing RF signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4 PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
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UM2742 List of tables
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List of tables
Table 1. TXCO / Crystal configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Table 2. MCU interfaces and buttons (see Figure 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Table 3. MCU - SPI interface and ST25RU3993 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Table 4. SPI interface pinout at J10, J12 and J13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Table 5. UART connections and pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Table 6. MCU connections to buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Table 7. MCU connections to LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Table 8. MCU connections to RF switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Table 9. Connections to JLINK (SWD) interface and pinout of connector . . . . . . . . . . . . . . . . . . . . 17Table 10. Typical voltage levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Table 11. Connection of components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Table 12. Connections of analog test points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Table 13. Supply voltages of analog test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Table 14. RF test points – Default power levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Table 15. List of schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Table 16. PCB stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Table 17. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Table 18. DC characteristics (VBUS = 5.0 V, 25 °C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Table 19. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
List of figures UM2742
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List of figures
Figure 1. ST25RU3993-HPEV board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Figure 2. Standard connection setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Figure 3. ST25RU3993-HPEV functional diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Figure 4. Power detector voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 5. Main digital interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Figure 6. JLink connection using the needle adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Figure 7. Entering the Boot mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 8. Test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 9. Connection of a voltmeter / ammeter to the supply voltage test points . . . . . . . . . . . . . . . 23Figure 10. RF test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Figure 11. Connecting to the RF test points with the SMA adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 12. System overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 13. UHF RFID reader IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Figure 14. External power amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Figure 15. Carrier cancellation circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Figure 16. Antenna switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Figure 17. RF shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Figure 18. USB supply / UART bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Figure 19. Microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Figure 20. Supply LDOs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Figure 21. External interfaces and connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Figure 22. Top layer layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Figure 23. RF GND layer (L2), GND layer (L4) and bottom layer (L6) layout . . . . . . . . . . . . . . . . . . . 39Figure 24. Power layer (L3) layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Figure 25. Routing layer (L5) layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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1 Standard connection setup
The typical reader setup is shown in Figure 2.
Figure 2. Standard connection setup
The host PC running the GUI is connected via a Micro-USB cable. The external power amplifier on the ST25RU3993-HPEV board is powered through the 6 V power adapter and must be connected when the external PA TX option is used. The antenna is connected to the active antenna port through a coaxial cable. A transponder is within the antenna range.
1.1 Board features
ST25RU3993 RAIN (UHF) RFID reader IC
ISO/IEC 18000-63:2015 / Gen2V2
GB/T 29768-2013
Two SW-controlled power amplifier (PA) options:
– External PA: 30 dBm max. TX power
– Internal PA: 17.5 dBm max. TX power
Configurable TX power level
Power detector to monitor TX power
Automatic carrier cancellation for improved RX sensitivity
Differential RX input
RX sensitivity:
– -80 dBm at 90% read success, one sideband of tag response (ISO18046-3: 2012)
– -77 dBm at 90% read success, both sidebands of tag response(ISO18046-3: 2020)
Adaptive / manual RX gain adjustment
Tunable radio frequency: 840 to 960 MHz
Minimum frequency step: 25 kHz
External frequency reference (20 MHz) assembly option
Adaptive / manual anti-collision slot options
Continuous wave or Modulated RF output test modes
Standard connection setup UM2742
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Two antenna ports: SMB (M)
Automatic / Manual antenna port switching
Carrier sense TX option (LBT)
UHF tag RSSI measurement
Configurable SELECT command mask
UHF transponder EPC Read / Write
Transponder read based applications trigger
Custom reader TX command editor tool
Customizable Gen2 TX commands
Direct TX modulation through MCU for proprietary protocol support
Store / Recall reader configuration
Register map
Buzzer
Host interface and supply
– USB/UART bridge
– USB receptacle: Micro, B-Type
– Main supply: 6 V DC jack
MCU:
– STM32L476RGT6 (Arm®(a) 32-bit Cortex®-M4)
– 64 MHz
– 128-Kbyte RAM
– 1-Mbyte Flash memory
– SPI Mode 1 (5 MHz)
– Firmware programmable through USB/UART
– SWD debug interface
– LED indicators
– Power amplifier selection
– Carrier cancellation tuning activity
– Carrier cancellation tuning OK
– OSC OK (20 MHz external reference)
– PLL OK
– RF ON
– No tag response
– Tag CRC error
– Tag found
Test points:
– In-circuit RF power levels and signals
a. Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.
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– RFID communication TX and RX
– UART and SPI signal lines
– UART_LOG for debugging purposes
– Control voltage of internal VCO
– RF power detector output voltage
– 20 MHz reference signal
– External PA BIAS voltage
– LDO output voltages
– LDO outputs: jumpers for current consumption measurement
– Main supply: jumper for current consumption measurement
– Antenna switch state
– Power amplifier selection switch state
Buttons:
– MCU reset
– MCU boot mode
Standard connection setup UM2742
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Figure 3. ST25RU3993-HPEV functional diagram
IRQ
EN
RF switch:
SKY13431-374LF
Carrier cancellation
circuit
SPI (Mode 1)
5V
RX
TX
D-
D+ USB connector:
MICRO-B
3.3V 3.6V
LDO:
LD39100PUR
PA_LDO_EN
PA_SW_V1
PA_SW_V2
ANT_SW_V2
ANT_SW_V1
CPL-10dB
CPL-20dB
RFOPX RFONX PAOUT_P PAOUT_N
93_RF_OUT
93_intPA
PA_OUT
LP_Filter_IN
LP_Filter_OUT
TX_RX
TX
Power detector:
MAX4003EUA
ANT1 ANT2
ETC_x
MOSI
CLK
RF_Detector
SWD connector: (TC2050-IDC-FP)
SWD
Buzzer:
PKMCS0909E4000
OSCO
3.3V
3.3V
3.3V
3.3V
3.3V
LDO:
LD39100PUR
LED: MCU
LED: RF ON
LED: Tuning
LED: Tuned
LED: OSC OK
LED: ANT1
LED: ANT2
LED: NO Tag Resp
LED: Tag CRC Err.
LED: Tag
LED: Int_PA
LED: Ext_PA
LED: PLL OK
SPI + IRQ + EN
Carrier cancellation CS
UART
UART_LOG_TX
PA_LDO_EN
OSCO
VCO
EXT_PA_BIAS
RF detector
Button: RESET
Button: BOOT
Legend
Component Test point / connector
LED Button Logic Supply
DC power jack OD: 6.4 mm ID: 2.1 mm
6V
OSCI
Antenna selection switch state
PA selection switch state
LED: BOOT (red)
VBUS 5V VBUS 5V
USB/UART bridge:
FT231XQ-R
Balun:
BD0810J50100AHF
20 dB coupler:
DC1722J5020AHF
Low pass filter:
0900LP15B0063
10 dB coupler:
DC1722J5020AHF
TCXO:
TXEAADSANF-20
Crystal:(optional)
NX3225SA-20
Antenna port 2
SMB Male
Antenna port 1
SMB Male
6V
VBUS 5V
4
3
4
RF Analog
RF switch:
SKY13431-374LF
PA LDO:
LD39100PUR
RX
MIX_INP
MIX_INN
MCU:
STM32L476RG
Power amplifier:
TQP9107
Balun:
BD0810J50100AHF
Balun:
0900BL15C050
UHF RFID reader IC:
ST25RU3993
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2 Hardware description
2.1 RF circuit
The main component of the RF circuit is the ST25RU3993 device, which receives digital baseband transmit data and commands from the MCU via the SPI interface. It then frames these data and automatically encodes them into PIE symbols. Based on the PIE encoded symbols ST25RU3993 creates a sinusoidal shaped modulation signal (either ASK or PR-ASK), which modulates the RF carrier. ST25RU3993 synthesizes its RF carrier frequency with a VCO / integer-n phase locked loop (PLL). The frequency reference for the PLL can be either a 20 MHz crystal oscillator or a temperature compensated crystal oscillator (TCXO).
As shown in Table 1 the ST25RU3993-HPEV board accommodates both options, the default configuration is the TCXO with a clipped sine wave output wave having 0.8 Vpp amplitude. With a small modification it is possible to connect the existing crystal.
The output of the internal PLL- charge pump is connected to LF_CEXT (pin 45), and the external part of the loop filter is placed in close proximity to it. An additional low-pass filter stage is integrated in ST25RU3993 and is part of the loop filter circuit. The loop filter output is the control voltage of the internal VCO.
Table 1. TXCO / Crystal configuration
Default Alternate (modified by user)
TCXO connected to ST25RU3993 Crystal connected to ST25RU3993
R54 and R55 not populated C51 removed, R54 and R55 populated
Hardware description UM2742
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The ST25RU3993 has two differential output port pairs. The low power output and the internal power amplifier output. Depending on which differential output port pair is activated the modulated carrier frequency will be amplified and output accordingly.
The low power output is intended for external signal amplification for a long read range configuration of the ST25RU3993-HPEV reader. The low power output with its differential output pin pairs RFONX (23) and RFOPX (24) is connected to a 2:1 balun, where the transmit signal is transformed from a 100 differential to 50 Ω single-ended signal. The output stage of the low power output is supplied by the VDD_B voltage generated and regulated by ST25RU3993 itself. L3 and L4 act as a RF choke, C57 and C58 as bypass capacitors and C65 and C54 as DC blocking capacitors. The signal then proceeds to the external power amplifier to generate a high-power output signal with approximately 31 dBm in ST25RU3993-HPEV default transmit power configuration.
The internal power amplifier is used for the short read range configuration of the reader. The output pins of the internal power amplifier are PAOUT_N (16, 17) and PAOUT_P (20, 21). A matching network and a 1:1 balun transforms the output of the internal power amplifier to a 50 Ω single-ended signal. The internal power amplifier is supplied by the on-chip generated and regulated voltage VDD_PA. L1, L2 are acting as RF chokes, C12 and C14 are bypass capacitors. After the balun the output power of the internal power amplifier is tipically 20 dBm.
Both RF output options the external power amplifier and the output of the internal power amplifier are connected to an RF-switch which is controlled by the PC software (GUI) of the ST25RU3993-HPEV reader. Only one RF output option can be active at a time. Note a UHF RFID reader reference would typically offer only one RF output and hence the PA RF-switch would be stripped from the design avoiding it’s introduced insertion loss of ~0.5 dB. So would be the DC blocking capacitors which this RF-switch requires on all its RF terminals. The output of the RF-switch is connected to a low-pass filter which attenuates the second and third harmonic of the carrier frequency. The filtered transmit signal is then connected to a 20 dB directional coupler, which takes a negligible small portion of the transmit power, which is further attenuated by a pi-pad attenuator. The limited TX power sample is then fed to the input a logarithmic power detector that converts the RF power to a corresponding DC voltage. The output DC voltage of the power detector versus the generated RF power is shown in Figure 4.
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Figure 4. Power detector voltage characteristics
The DC output voltage of the power detector is connected to an ADC input pin (PA1) of the microcontroller.
The majority of RF transmit power which passes through the 20 dB directional coupler is fed to the main directional coupler. The main directional coupler has a coupling factor of 10 dB and acts as the directional unit which should isolate the transmit from the receive path of ST25RU3993. The main directional coupler plays a very important role in the RFID reader system as its parasitics have a great influence on the sensitivity of the reader. The main directional coupler essentially has four terminals:
1. Input
2. Direct
3. Coupled
4. Isolated
The direct terminal is connected to the second RF switch in the reader system. This switch directs the transmit power to either antenna port 1 or antenna port 2. The antenna switch again requires DC blocking capacitors on all its RF terminals. Both antenna ports are SMB (male) type.
To avoid reducing the sensitivity of the reader the self-jamming signal reaching the receiving inputs of ST25RU3993 must be minimized. The self-jamming signal comprises reflections from the antenna (S11) and the leakage across the main directional coupler. To minimize it a carrier cancellation circuit is connected to the coupled port of the main directional coupler.
Hardware description UM2742
12/44 UM2742 Rev 2
The carrier cancellation circuit is able to change its impedance and hence to reflect a certain amount of the coupled power back into the directional coupler. This reflected signal is combined with the self-jamming signal at the isolated port of the main directional coupler. The isolated port of the main directional coupler is connected to the receiving pins of ST25RU3993. If the signal reflected by the carrier cancellation circuit has the same amplitude and opposite phase of the self-jammer the signals cancel them out and vanish.
The main components of the CCC are three digital tunable capacitors controlled by the STM32L476RG microcontroller via SPI. The lumped components of the carrier cancellation circuit help to define its tuning range around 50 Ω and define the impedance step created by one LSB change of a digital tunable capacitor.
The isolated port of the main directional coupler is connected to a 2:1 balun to transform the incoming tag response signal to a 100 Ω differential signal that is fed into ST25RU3993 receiver section at pins MIX_INP (4) and MIX_INN (6).
2.2 Microcontroller and connections
Table 2. MCU interfaces and buttons (see Figure 5)
A MCU reset button
B USB receptacle: Micro, B-Type
C 6 V DC power connector: 5 mm barrel connector
D ST25RU3993 Rain (UHF) RFID reader IC
E Enable line connection of power amplifier LDO
F UART interface connections
G MCU boot mode button
H STM32L476RGT6 (Arm® 32-bit Cortex®-M4)
J SWD debug interface connections
L, M SPI bus interface connections
N UART_LOG connection for debugging purposes
K Carrier cancellation circuit (CCC) SPI chip select lines
O PA output selection switch state
P Antenna port selection switch state
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Figure 5. Main digital interfaces
The ST25RU3993-HPEV is controlled by STM32L476RG, a ultra-low-power MCU with FPU Arm Cortex-M4 core, 80 MHz, 1 Mbyte Flash memory, LCD, USB OTG, DFSDM.
MS53587V1
A B C
O
P
F
K
L
N
M D
E
JHG
Hardware description UM2742
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The MCU is supplied by 3.3 Volts, regulated by an adjustable LDO. The clock source is an external crystal generating 32.768 kHz, connected to OSC32_in (3) and OSC32_out (4). It interfaces the host PC via UART for which a USB/UART bridge is used.
The MCU communicates with the ST25RU3993 via an SPI interface controlling the ST25RU3993 lines ENABLE and IRQ. The SPI interface operates in mode 1 with a 6 MHz serial clock. The SPI interface is also used to control the digital tunable capacitors for the carrier cancellation circuit.
The MCU controls the RF switches for changing the power amplifier and the active antenna port. The analog output of the RF power detector is connected to one of its ADC inputs (PA1) to convert the DC voltage corresponding to the transmit RF power into a digital representation. The LDO for the external power amplifier is enabled by the MCU, making it possible to completely shut down the external power amplifier when RF power needs to be OFF, e.g. as required for carrier sense (LBT). One pin (UART LOG) is reserved to act as a generic debug pin or to be programmed as a trigger output for an external measurement equipment.
Table 3. MCU - SPI interface and ST25RU3993 connections
Component U1 Component U5 Component U6 Component U7 Component U8
MCU pin ST25RU3993 pin DTC1 pin DTC2 pin DTC3 pin
Name Number Name Number Name Number Name Number Name Number
PA4 20 NCS 33 - - - - - -
PA5 21 SCLK 37 CLK 5 CLK 5 CLK 5
PA6 22 MISO 34 - - - - - -
PA7 23 MOSI 35 SDAT 7 SDAT 7 SDAT 7
PC7 38 - - - - - - SEN 6
PC8 39 - - - - SEN 6 - -
PC9 40 - - SEN 6 - - - -
PA9 42 IRQ 32 - - - - - -
PA10 43 EN 31 - - - - - -
Table 4. SPI interface pinout at J10, J12 and J13
Component U5 Component U6 Component U7 Component U8 J10 J12 J13
ST25RU3993 pin DTC1 pin DTC2 pin DTC3 pin Connectorpin number
Name Number Name Number Name Number Name Number
SCLK 37 CLK 5 CLK 5 CLK 5 1 - -
MISO 34 - - - - - - 3 - -
MOSI 35 SDAT 7 SDAT 7 SDAT 7 2 - -
- - - - - -ETC3SEN
6 - 3 -
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- - - -ETC2SEN
6 - - - 2 -
- -ETC1SEN
6 - - - - - 1 -
OAD2 - - - - - - - - - 1
OAD - - - - - - - - - 2
EN 31 - - - - - - - - 3
IRQ 32 - - - - - - - - 4
NCS 33 - - - - - - - - 5
ADC - - - - - - - - - 6
Table 4. SPI interface pinout at J10, J12 and J13 (continued)
Component U5 Component U6 Component U7 Component U8 J10 J12 J13
ST25RU3993 pin DTC1 pin DTC2 pin DTC3 pin Connectorpin number
Name Number Name Number Name Number Name Number
Table 5. UART connections and pinout
Component U1 Component U13 J7
MCU pin FTDI pinConnector pin
numberName Number Name Number
NRST 7 RTS 19 1
BOOT0 60 DTR 18 2
PA3 17 TXD 17 3
PA2 16 RXD 1 4
Table 6. MCU connections to buttons
Component U1 Component B1 Component B2
MCU pin Reset button Boot button
Name Number Name Number Name Number
NRST 7 1 1 2 2
BOOT0 60 - - 5 5
Hardware description UM2742
16/44 UM2742 Rev 2
Table 7. MCU connections to LEDs
Component U1D1 D2 D3 D4 D5 D6 D7 D8 D11 D12 D13 D16 D17
MCU pin
Na
me
Nu
mb
er
MC
U_
LE
D
intP
A_L
ED
RF
_LE
D
extP
A_
LE
D
TU
NIN
G_L
ED
TAG
_L
ED
PL
L_L
ED
OS
C_L
ED
TU
NE
D_L
ED
NO
_RE
SP
_LE
D
CR
C_E
RR
_LE
D
AN
T1_
LE
D
AN
T2_
LE
D
PA0 14 1 (C) - - - - - - - - - - - -
PD2 54 - 1 (C) - - - - - - - - - - -
PC10 51 - - 1 (C) - - - - - - - - - -
PB4 56 - - - 1 (C) - - - - - - - - -
PC12 53 - - - - 1 (C) - - - - - - - -
PC8 37 - - - - - 1 (C) - - - - - - -
PB12 33 - - - - - - 1 (C) - - - - - -
PB13 34 - - - - - - - 1 (C) - - - - -
PC11 52 - - - - - - - - 1 (C) - - - -
PB14 35 - - - - - - - - - 1 (C) - - -
PB15 38 - - - - - - - - - - 1 (C) - -
PB2 28 - - - - - - - - - - - 1 (C) -
PB1 27 - - - - - - - - - - - - 1 (C)
Table 8. MCU connections to RF switches
Component U1 Component S1 Component S2
MCU pin PA switch pin Antenna switch pin
Name Number Name Number Name Number
PB0 26 V1 1 - -
PC5 25 V2 3 - -
PB10 29 - - V1 1
PB11 30 - - V2 3
UM2742 Rev 2 17/44
UM2742 Hardware description
43
2.3 Firmware programming
There are two options to program the firmware of the STM32L476RG microcontroller:
1. The simplest way to program a new firmware version to the MCU is by connecting the ST25RU3993-HPEV board to the host PC with the micro USB cable and use the Firmware Update function of the GUI. For more information about this option refer to the user manual of the GUI.
2. Alternatively, the firmware can be programmed to the MCU using the ST-LINK connected to the JLINK (SWD) interface (see Figure 6) with a J-Link needle adapter (e.g. 8.06.04 J-LINK 10-PIN NEEDLE ADAPTER). For more information about this option refer to the user manual of the ST-LINK/V2.
Table 9. Connections to JLINK (SWD) interface and pinout of connector
Component U1 Component P3
MCU pin JLINK pin
Name Number Name Number
- - VDD 1
PA13 46 SWDIO 2
- - GND 3
PA14 49 SWCLK 4
- - GND 5
PB3 55 SWO 6
- - NC 7
PA15 50 TDI 8
- - NC 9
NRST 7 MCU RESET N 10
Hardware description UM2742
18/44 UM2742 Rev 2
Figure 6. JLink connection using the needle adapter
UM2742 Rev 2 19/44
UM2742 Hardware description
43
2.4 Boot mode
To enter the STM32L476RG boot mode press and hold the BOOT button (1) while the RESET button (2) is pressed (see Figure 7). At this point the boot mode is active and both buttons can be released.
Figure 7. Entering the Boot mode
2.5 Power supply
The ST25RU3993-HPEV is supplied through the USB Interface (VBAT) and an external 6 V supply connected to J14 a DC power jack. J14 has a hot inner contact with 2.1 mm diameter suitable for a 5.5 mm barrel plug.
MS53599V1
2
1
Hardware description UM2742
20/44 UM2742 Rev 2
The 5V (VBAT) supply rail is distributed to two low-dropout regulators which supply:
LDO U9 – for powering digital components (3V3),
LDO U10 - for powering RF components (VSUP)
The 6 V DC input is dedicated to supply the power amplifier supply via an LDO U11 regulating the supply rail VPA.
Table 10. Typical voltage levels
Voltage domain Voltage (V)
3V3 3.3
VSUP 3.6
VPA 5.0
Table 11. Connection of components
Voltage domain Schematic Component(s) Pin name(s) Pin number(s)
5 V (VBUS)
Supply (Figure 20) U9, U10VI 6
EN 1
USB interface (Figure 18)
U13 VCC 12
6 V Supply (Figure 20) U11VI 6
EN 5
3V3
External interfaces (Figure 21)
P3 1 1
Controller (Figure 19)
U1
VBAT 1
VDD 19, 32, 48, 64
VDD / VREF+(1) 13
NRST(2) 7
BOOT0(3) 60
Power amplifier (Figure 14)
U3VCC 8
/SHDN 2
UHF_RFID (Figure 13)
U4 VCC(4) 4
U5 VDD_IO 38
Carrier cancellation (Figure 15)
U6, U7, U10 VDD 4
USB interface (Figure 20)
U13 VCCIO 20
VSUP (3.6 V)UHF_RFID (Figure 13)
U5 VEXT(5) 11
U5 VEXT_PA(6) 14
UM2742 Rev 2 21/44
UM2742 Hardware description
43
VPA (5 V)Power amplifier
(Figure 14)
U2 VPD1 12
U2 VPD2 11
U2 VCC 2
U2 VBIAS(7) 1
1. Via ferrite bead FB3.
2. Via pull-up resistor R61.
3. Via push button B2.
4. Via ferrite bead FB4.
5. Via ferrite bead FB5.
6. Via ferrite bead FB1.
7. Via R21.
Table 11. Connection of components (continued)
Voltage domain Schematic Component(s) Pin name(s) Pin number(s)
Hardware description UM2742
22/44 UM2742 Rev 2
2.6 Test points
The ST25RU3993-HPEV board provides several test points (see Figure 8) that allow the user to test and evaluate circuit nodes in the ST25RU3993 reader design.
Figure 8. Test points
MS54000V1
5 V
3.3 V
VPA
VSUP
ATP3ATP4ATP1
Digital
ATP2
UM2742 Rev 2 23/44
UM2742 Hardware description
43
2.6.1 Analog test points
Two test points are placed at the output of the three LDOs to easily measure the regulated voltage of each voltage domain. A GND pad is placed close to the voltage test points for accurate voltage measurements (left side of Figure 9).
The current consumption of the three regulated voltage domains can be measured separately. To enable this kind of measurement a 0 Ω resistor (R3) must be removed (right side of Figure 9). Make sure to restore the connection once the measurement is done, before reverting to normal operation.
Figure 9. Connection of a voltmeter / ammeter to the supply voltage test points
Table 12. Connections of analog test points
Component U5 U2 U3
Pin Name Number Name Number Name Number
Test point
ATP1 OSCO 30 - - - -
ATP2 VCO (LF_CEXT) - - - -
ATP3 - - VBIAS 1 - -
ATP4 - - - - OUT 7
Table 13. Supply voltages of analog test points
5 V (VBUS) 3V3 digital supply VSUP RF VPA power amplifier
P2 J5 J20 J21
Pin no. Pin name Pin no. Pin name Pin no. Pin name Pin no. Pin name
1 VBUS 1 GND 1 GND 1 GND
2 VBUS 2, 3 3V3 2, 3 VSUP 2, 3 VPA
MS54018V1
ARemove R3
V
Hardware description UM2742
24/44 UM2742 Rev 2
2.6.2 Digital test points
In addition to the four test points shown above a test point for each LED connected to the STM32L476RG controller is available.
2.6.3 Probing RF signals
The ST25RU3993-HPEV board features four RF test points (see Figure 10) to measure RF power levels in-circuit. The test point connectors have a switch built-in that disconnects the remainder of the circuit when the test adapter (MS-156-HRMJ-2) is mated. This allows the user to perform measurements with a proper line termination.
PLL OK Indicates that the PLL of ST25RU3993 is locked and the carrier frequency is stable.
OSC OK Active low. Indicates that the reference frequency for the PLL is stable.
No tag response :Pulled low if the sent reader command is not replied by a tag.
Tag CRC error Pulled low if a CRC error is detected within a tag response.
Tag found Pulled low every time a tag has been inventoried.
EXT_PA Pulled low if the reader is in its long read range configuration.
INT+PA Pulled low if the reader is in its short read range configuration.
TUNING Pulled low if the reader currently is re-tuning the carrier cancellation circuit.
Tuned Active low. Indicates that the self-jamming signal is sufficiently suppressed.
RF ON Active low. Indicates that the RF carrier is ON.
ANT1 Active low. Indicates that antenna port 1 is active.
ANT2 Active low. Indicates that antenna port 2 is active.
UM2742 Rev 2 25/44
UM2742 Hardware description
43
Figure 10. RF test points
MS54019V1
RF-TP2RF-TP1
RF-TP3
RF-TP4
Hardware description UM2742
26/44 UM2742 Rev 2
Figure 11. Connecting to the RF test points with the SMA adapter
Table 14 lists the typical power levels that can be expected while the ST25RU3993-HPEV board operates in its default configuration.
Table 14. RF test points – Default power levels
RF test point Description Power level
RF-TP1ST25RU3993 RF output signal (single-ended). To evaluate the power and the spectral properties of the RF signal at the low power output.
-1.9 dBm
RF-TP2External power amplifier output. To evaluate the power and the spectral properties of the RF signal.
33 dBm
RF-TP3Internal power amplifier RF output. To evaluate the power and the spectral properties of the RF signal.
20.5 dBm
RF-TP4RX signal. To evaluate the self-jammer signal level or a RN16 tag response. When connected no tag communication is possible.
-
UM2742 Rev 2 27/44
UM2742 Schematics
43
3 Schematics
Table 15. List of schematics
Module Reference
System overview Figure 12
UHF RFID reader IC Figure 13
External power amplifier Figure 14
Carrier cancellation circuit Figure 15
Antenna switch Figure 16
RF shield Figure 17
USB supply / UART switch Figure 18
Microcontroller Figure 19
Supply LDOs Figure 20
External interfaces and connectors Figure 21
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Figure 12. System overview
1
1
2
2
3
3
4
4
D D
C C
B B
A A
93_RF_OUT
SPI
93_Signals
RX_D
93_intPA
OSCO
VCO
UHF RFID ReaderUHF_RFID_HP.SchDoc
93_RF_OUT TX
PA_SW_V2
RF_Detector
93_intPA
ext_PA_BIAS
PA_SW_V1
Power AmplifierPower_Amplifier_HP.SchDoc
Project PageProject_Page_HP.SchDoc
SPI
93_Signals
Carrier_CancellationJLINK
PA_LDO_EN
MUC_RESET_N
UART_LOG_TX
OSCO
VCO
ext_PA_BIAS
RF_Detector
UART
ANT_SW_V1
ANT_SW_V2
PA_SW_V2
PA_SW_V1
External InterfacesExternal_Interfaces_HP.SchDoc
SPI
UART
93_Signals
JLINKCarrier_Cancellation
PA_LDO_EN
PA_SW_V2
MUC_RESET_N
UART_LOG_TX
ANT_SW_V1
RF_Detector
PA_SW_V1
ANT_SW_V2
Plug_Enable
ControllerController_HP.SchDoc
TX
Carrier_Cancellation
SPI
RX_D
TX_RX
Carrier CancellationCarrier_Cancellation_HP.SchDoc
PA_LDO_ENPlug_Enable
DC SupplySupply_HP.SchDoc
Title PageTitle_Page_HP.SchDoc
UART
USB InterfaceUSB_Interface_HP.SchDoc
MechanicalMechanical_HP.SchDoc
ANT_SW_V2
TX_RX
ANT_SW_V1
Antenna SwitchAntenna_Switch_HP.SchDoc
UM
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Figure 13. UHF RFID reader IC
1
1
2
2
3
3
4
4
D D
C C
B B
A A
NC
S
GNDGND
GNDGND
GND GND
GNDGND
GND
GND
GND
GND GND
MIS
O
MO
SI
CLK
IRQ
EN
LF_CEXT
LF_CEXT
GND GND
VDD_B
VDD_B
GND
GND
93_RF_OUT
OA
D
OA
D2
GND
GND
VSUP
MISOMOSI
CLKSPI
IRQEN
NCSADCOAD
OAD2
93_Signals
IRQ
GND
GNDGNDGNDGND
GNDGNDGNDGNDGNDGND
RX_P
RX_N
RX_D
CLK
MOSIMISO
NCS
EN
OADOAD2
R33
15k
C553n9F
C50100nF
C592u2F
C612u2F
C632u2F
C71
2u2F
C73
2u2F
C75
2u2F
C852u2F
C84
2u2F
C522u2F
C892u2F
C782u2F
C7910nF
C8010nF
C8110nF
C8210nF
RFO_P
RFO_N
TX
_P
TX
_N
IN_
P
IN_
N
RX_P
RX_N
RFO_P
RFO_N
GND
Vdd_PA
GND
GND
GND
GND
C3
1p2F
C1
1p2F
L230nH
L130nH
C4
15pF
C5
15pF
C75p6F
C65p6FL15
3n6H
L103n6H
GND 2
UB 1
B24
B13
NC6GND
UB
B2
B1
NC
GND 5
T3Balun
93_intPA
Vdd_PA
GND
VBPD
GND
GND
GND
R540R DNP
R55
0R DNPADC
3V3
3V3
ADC
X320 MHZ
CD2
CD1
AGD
VOSC
VDD_A
VDDLF
COMP_A
CO
MN
_A
COMP_B
CO
MN
_B
CB
V
CB
IB
VD
D_
MIX
PAOUT_N
PAOUT_P
OS
CO
OS
CI
OSCO
VCO
GND GND
C662u2F
C76120pF
C7230 pF
C3430 pF
C7430 pF
C64
120pF
C62120pF
C60120pF
Low ESL
C69100nF
C9382pF
C9482pF
GNDG1
GNDG2
IO
J9
COAX JACK
C14120pF
C12120pF
C5482pF
C6582pF
C57120pF
C58120pF
C51220nF
FB4
1k
C11111pF
C11011pF
GND
C3282pF
COMN_A48
CO
MP
_B1
CO
MN
_B
2
VD
D_L
FI
3
MIX
_IN
P4
MIX
_IN
N6
VS
S/M
IXS
_IN
5
CB
IB9
VD
D_M
IX10
CB
V8
VD
D_T
XPA
B7
VE
XT
11
VDD_PA13
VD
D_B
12
PAOUT_N17
PAOUT_N16
VEXT_PA14
VSN15
VSN18
VSN19
PAOUT_P20
PAOUT_P21
VSN22
OA
D2
26
OA
D2
7
RFONX23
RFOPX24
VS
N2
5
OS
CO
30
VD
D_D
28
EN
31
IRQ
32
OS
CI
29
NC
S3
3M
ISO
34
MO
SI
35
CL
SY
S3
6
SCLK37
VDD_IO38
CD240
CD141
AGD42
ADC39
VDD_A44
LF_CEXT45
VOSC43
VDDLF46
COMP_A47
49 EP
ST25RU3993UHF RFID
Integrated Reader IC
U5ST25RU3993
C91
0.47uF
VEXT_PA
VEXT_PA
FB5
1kLow ESL
C86100nF
Low ESL
C83
100nF
Low ESL
C88100nF
Low ESL
C77100nF
Low ESL
C67100nF
GND
C902u2FGND
C132u2F
L430nH
L330nH
C56150pF
FB1
330R
UB 1
GND 2B13
B24NC6
UB
GND
B1
B2
NC
GND 5
T5
BD0810J50100A00
GND 1
GND 2OUT3VCC4
U4
TCXO 20.000MHZ
C9210uF
Sc
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Figure 14. External power amplifier
1
1
2
2
3
3
4
4
D D
C C
B B
A A
93_RF_OUT
GND
PA_OUT
R100R
R200R
C104
0.47uF
GND
VPA
GND
C160.47uF
VPA
GN
DG
1
GN
DG
2
I O
J6COAX JACK
GN
DG
1
GN
DG
2
I O
J1COAX JACK
GND
C1052u2F
GND
GND
93_intPA
GND
PA_SW_V2
RFIN1
/SHDN2
GND3
CLPF4 GND 5NC 6
OUT 7VCC 8RFIN
/SHDN
GND
CLPF GND
NC
OUT
VCCU3
Log Detect
GND GND
GNDGND
C152u2F
C70120pF
3V3
Detector
GND
R2251.1R
RF_Detector
TX
EXT_PA_BIAS
GND
PA_SW_V1RF16
RF24
GND5V1 1
RFC 2
V2 3
RF1
RF2
GNDV1
RFC
V2EP7
S1
SP2T
R2562R
R4562R
R24
249R
LP_Filter_IN
LP_Filter_OUT
C108
82pF
C10782pF
C109
82pF
R21
100R
C172n2F
R23
52.3R
NC
2N
C6
IN8 OUT 4
NC
NC
IN OUT
GN
D1
GN
D7
GN
D3
GN
D5
T1
LOWPASS FILTER
VB
IAS
1
VC
C2
NC
3
NC
4
NC
6N
C5
NC
9N
C10
NC
8
RFO
UT
7
VP
D2
11
RFI
N13
VP
D1
12E
xpos
ed P
ad14
U2
TQP9107
C2010uF
Input6
Isolated 2Direct 1
Coupled5
GND 3GND4
Input
Isolated
Direct
Coupled
GNDGND
T220 dB Dir Coupler
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Figure 15. Carrier cancellation circuit
1
1
2
2
3
3
4
4
D D
C C
B B
A A
GND
GND
ETC_1
ET
C_
2
ETC_3
GND
GND
GND
GND
GND
GND GND
RX_P
RX_N
RX_D
ETC_1ETC_2ETC_3
Carrier_Cancellation ETC_3ETC_2ETC_1
MISOMOSI
CLKSPI
CLK
MOSI
MOSI
MO
SI
MOSI
R34
0R
R35100R DNP
CLK
CL
K
CLK
GND
3V3
3V3
3V3
L116n8H
C37
1p6F
GND GND
C182u2F
C53120pF
GNDGND
C872u2F
C95
120pF
GNDGND
C192u2F
C68120pF
GND
RF_neg1
RF_neg2
GN
D3
VDD4
SC
LK5
SE
N6
SD
AT7
RF_pos 8RF_pos 9
GN
D10
RF_neg
RF_neg
GN
D
VDD
SC
LK
SE
N
SD
AT
RF_pos
RF_pos
GN
D
U7
PE64906MLAA-Z RF_
neg
1
RF_
neg
2
GND 3
VD
D4
SCLK5
SEN6SDAT7
RF_
pos
8R
F_po
s9
GND 10
RF_
neg
RF_
neg
GND
VD
D
SCLK
SEN
SDAT
RF_
pos
RF_
pos
GND
U8
PE64906MLAA-Z
RF_
neg
1R
F_ne
g2
GND3
VD
D4
SCLK 5
SEN 6SDAT 7
RF_
pos
8
RF_
pos
9
GND10
RF_
neg
RF_
neg
GND
VD
D
SCLK
SEN
SDAT
RF_
pos
RF_
pos
GND
U6PE64906MLAA-Z
GND
TX TX_RX
GND
GN
DG
1
GN
DG
2
I O
J3COAX JACK
UB1
GND2B1 3
B2 4NC 6
UB
GND
B1
B2
NC
GND5
T6
BD0810J50100A00
Direct 6
Coupled2Input1
Isolated 5
GND3 GND 4
Direct
Coupled
Input
Isolated
GND GND
T4
10dB Dir Coupler
R26110R
L126n2H
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Figure 16. Antenna switch
Figure 17. RF shield
GND
GND
C36
82pF
C3582pF
GND
TX_RX
ANT_SW_V2
ANT_SW_V1 RF1 6
RF2 4
GND 5V11
RFC2
V23
RF1
RF2
GNDV1
RFC
V2EP 7
S2
SP2T
C112
82pF
P5
SMB JACK STR 50OHM EDGE MNT
P4
SMB JACK STR 50OHM EDGE MNT
GND
GND1
GND2
GND3
GND4
GND5
GND6
GND7
GND8
GND9
GND10
GND11
GND12
GND13
GND14
GND15
GND16
GND17
GND18
GND19
GND20
GND21
GND22
GND23
GND24
GND25
GND26
GND27
GND28
SHIELD1
CRS-50.80X38.1
GND
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Figure 18. USB supply / UART bridge
1
1
2
2
3
3
4
4
D D
C C
B B
A A
GND
GND
R41 27R
R4727R
C10147pF
C10247pF
GND GND
C103100nF
GND
VBUS
GND
3V3OUT
3V3
GND
GND
UART_RTSUART_DTR
UART_TXUART_RX UART
D_CON_N
D_CON_P
D_ESD_N
D_ESD_P
GND
PWR1
D-2
D+3
ID4
Shield6
GND5
P1μUSB 3V3OUT
10
VC
C1
2
CBUS015
GN
D3
VC
CIO
20
RXD1
RTS#19
TXD17
CTS#6
USBDP8
RESET#11
USBDM9
GN
D1
3
GN
D2
1
CBUS114
CBUS27
CBUS316
DTR#18
DSR#4
DCD#5
RI#2
U13FT231XQ-R
GND
R8620R
C961uF
GND
R890R
R60R
GND
UResetLow ESL
C98100nF
VCC1
IO12
IO23
GND4
VCC8
IO17
IO26
GND5
VCC
IO1
IO2
GND
VCC
IO1
IO2
GND
U14USB6B1
D_CMC_N
D_CMC_P
GND
12
P2Header 2H
C991uF
GND
C236u8F
C302u2F
C332u2F
UReset
D21TVS
D20TVS
GND
TX
RX
RTS
DTR
C974u7F
C1004pF
FB7
31 Ohm
1
4
2
3
T8744231091
Sc
he
ma
tics
UM
274
2
34/4
4U
M2
742 R
ev 2
Figure 19. Microcontroller
1
1
2
2
3
3
4
4
D D
C C
B B
A A
MISOMOSI
CLKSPI
IRQEN
NCSADCOADOAD2
93_Signals
IRQ
CLK
MOSIMISO
NCS
EN
OADOAD2
ETC_1ETC_2ETC_3
Carrier_CancellationETC_3ETC_2ETC_1
NCS
MISOMOSI
ETC_1ETC_2ETC_3
IRQEN
GND GND
OSC32_INOSC32_OUT
OSC32_IN OSC32_OUT
VDDA
VDDA
UART
PA_LDO_EN
MCU_LED
extPA_LED
TUNED_LED
SWDIOSWCLK
SWOTDI
JLINK
RF_LED
MCU_LED
extPA_LED
RF_LED
R7 0RR8 0RR9 0RR11 0R
R12 0RR13 0R
D2LED BL
D1LED BL
D3LED BL
D4LED BL
C25100nF
PA_SW_V2CLK
B1
RESET
R43 0R
R38 0RR39 0RR40 0R
R37 0RR36 0R
3V3
PA014PA115
PA216
PA317PA420
PA521PA622
PA723PA841
PA942
PA1043PA1144
PA1245PA1346
PA1449PA1550
PB026PB127
PB228PB355
PB456PB557
PB658
PB759PB861
PB962PB1029
PB1130PB1233
PB1334
PB1435PB1536
PC0 8PC1 9
PC2 10
PC3 11PC4 24
PC5 25PC6 37
PC7 38PC8 39
PC9 40
PC10 51PC11 52
PC12 53PC13 2
PC14-OSC32_IN 3PC15-OSC32_OUT 4
PD2 54
PH0-OSC_IN 5PH1-OSC_OUT 6
NRST 7BOOT0 60
PA0PPPA1PA2PA3PA4PA5PA6PA7PA8PA9PA10PA11PPPA12PA13PA14PA15
PB0PB1PB2PB3PB4PB5PB6PB7PB8PB9PB10PB11PB12PB13PB14PB15
PC0PC1PC2PC3PC4PC5PC6PC7PC8PC9
PC10PC11PC12PC13
PC14-OSC32_INPC15-OSC32_OUT
PD2
PH0-OSC_INPH1-OSC_OUT
NRSTBOOT0
U1ASTM32L476RGT6
VBAT1
VDDUSB 48
VSS 18VSS 31VSS 47VSS 63
VSSA/VREF- 12
VDDA/VREF+13 VDD 19
VDD 32
VDD 64
VBAT
VDDUSB
VSSVSSVSSVSS
VSSA/VR/ EF-
VDDA/VR// EF+VDDVDDVDD
U1BSTM32L476RGT6
3V3
intPA_LED
D5LED BL
intPA_LED
TAG_LEDD6
LED BL
TAG_LED
PLL_LEDD7
LED BL
OSC_LEDD8
LED BL
PLL_LEDOSC_LED
R1610k
R56 0RR57 0R
UART_RTSUART_DTR
UART_TXUART_RX
MUC_RESET_N
R58 0R UART_LOG_TX
Reset
1 2D9
BAT60JFILM
12
D10BAT60JFILM
3V3
B2Boot
3V3
Boot0
Boot0
R61
10k TUNING_LED
D11LED BL
TUNING_LED
NO_RESP_LED
NO_RESP_LED
CRC_ERR_LED
CRC_ERR_LED
MCU
extPA
intPA
TAG
TUNING
TUNED
RF
PLL
OSC
NO_RESP
CRC_ERR
TUNED_LED
GND
ANT1_LEDD16
LED BLANT1
ANT2_LEDD17
LED BLANT2
ANT1_LEDANT2_LED
X1
NX3215SA-32.768K-STD-MUA-14
C94p7F
C104p7F
FB3
1kC262u2F
C80.47uF
C20.47uF
Lo
w E
SL
C27100nF
Lo
w E
SL
C28100nF
Lo
w E
SL
C29100nF
Lo
w E
SL
C31100nF
RF_Detector
Reset
TP5
TP6
TP7
TP8
TP9
TP10
TP11
TP12
TP13
TP14
TP15
TP16
TP17
BZ1Buzzer
GND
PA_SW_V1
ANT_SW_V2
ANT_SW_V1
D12`LED RD
D13`LED RD
D15`LED RD
R66
220
R65
220
R83
220
R82
220
R53
220
R52
220
R18
220
R17
220
R64
220
R51
220
R50
220
R15
220
R14
220
R81220
C1110uF
Plug_Enable
R92 0R
R93 0R
R90 0R
R91 0R
UM
27
42S
chem
atics
UM
2742
Re
v 235
/44
Figure 20. Supply LDOs
1
1
2
2
3
3
4
4
D D
C C
B B
A A
VPA
GND
GND
PA_LDO_EN
GND
VSUP
GND
GND
GNDGND
3V3
GND
R31
10k
R29
10k
R27
10k
3.6V
R4431k6
VBUS
GND GND GND
5V
3.3V
GND GNDGNDGND
C49
0.47uF
C47
0.47uF
C45
0.47uF
C43
0.47uF
C39
0.47uF
C41
0.47uF
EN1
GND2VO 4
ADJ 5EP
0
VI6PG 3
U10LD39100PUR
EN1
GND2VO 4
ADJ 5EP
0
VI6PG 3
U9LD39100PUR
GND
R1
0R
R2
0R
R3
0R
GND
GND
VBUS
6V
R3090.9k
1 2 3
J5 Header3_THMD DNP
1 2 3
J20 Header3_THMD DNP
1 2 3
J21 Header3_THMD DNP
R2835k7
C382u2F C40
2u2F
C422u2F
C442u2F
C462u2F
C482u2F
EN5
GND3VO 1
ADJ 2
EP
0
VI6PG 4
U11LD39200PUR
1
2
3
2472149
J14
DC_Jack
C1066u8F
3V3
C21
1uF
C22
1uF
FB2
31 Ohm
6V
C242u2F
R32
100K
GND
Plug_Enable
GND GND GND GND
Sc
he
ma
tics
UM
274
2
36/4
4U
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742 R
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Figure 21. External interfaces and connections
1
1
2
2
3
3
4
4
D D
C C
B B
A AMISOMOSI
CLKSPI
IRQEN
NCSADC
OADOAD2
93_Signals
ETC_1ETC_2ETC_3
Carrier_Cancellation
SWD
SWDIOSWCLKSWOTDI
JLINK
PA_LDO_EN
3V3
123456
J12
Header6_THMD DNP
MUC_RESET_N
UART_LOG_TXPA_LDO_EN
UART_LOG_TX
GND
OSCO OSCO
123456789
10
P3
TC2050-IDC-FP
TP1
VCOTP2
VCO
D28
TVS
D29
TVS
D30
TVS
D31
TVS
D32
TVS
D23TVS
D24TVS
D25TVS
D26TVS
D27TVS
D22TVS
D34TVS
D35TVS
D36TVS
D37TVS
D38TVS
D33TVS
D52TVS
D45TVS
EXT_PA_BIASTP3
EXT_PA_BIAS
TP4RF_Detector
UARTUART_RTSUART_DTR
UART_TXUART_RX
D48TVS
D49TVS
D50TVS
D47TVS
123
J8
Header3_THMD DNP
123
J15
Header3_THMD DNP
123
J2
Header3_THMD DNP
123
J10
Header3_THMD DNP
123
J13
Header3_THMD DNP
1J4
Header1_THMD - DNP
1J11
Header1_THMD - DNP
1234
J7
Header4_THMD - DNP
R46
220
R42
220
R19
220
R5
220
R4
220
12
J31
DNP
12
J30
DNP
PA_SW_V2
PA_SW_V1
ANT_SW_V2
ANT_SW_V1
UM2742 Rev 2 37/44
UM2742 PCB
43
4 PCB
The ST25RU3993-HPEV board has in total six layers. The dielectric material between all copper layers is FR-4 type. No blind or buried vias are used.
All components and almost all interconnections are on the top layer (Figure 22).
Impedance-controlled RF traces such as singled-ended 50 Ω (CBCPW) and differential 100 Ω traces are located on the top layer. For best ground connection all component ground terminals have a direct connection to the surrounding GND plane. This means that no thermal relief-connection exist.
The RF GND layer directly below the top layer is needed for the 50 Ω and 100 Ω waveguide traces. The spacing between top layer and RF GND layer is relevant for the impedance of the waveguides. RF currents tend to run back to their source directly underneath the waveguides, so it is important that the RF GND layer is solid and uninterrupted especially underneath the RF traces, to provide a direct path for the RF return currents.
The Power layer (Figure 24) is used to distribute the supply voltages through power planes, and only a few traces are on it.
The Routing layer (Figure 25) is used to interconnect the components minimizing cross-talk effects on RF traces.
Table 16. PCB stack
SchemeLayer Dielectric
Name Type Material Th (mm) Material Ɛr
Top overlay Overlay
Top solder Solder mask/Coverlay Surface 0.01016 Solder resist 4.5
Top layer Signal Copper 0.043 -
Dielectric 1 Dielectric Core 0.25 FR-4 (R-1755M) 4.7
RF GND Signal Copper 0.032 -
Dielectric 2 Dielectric Prepreg 0.1 FR-4 (R-1755M) 4.6
Power Signal Copper 0.032 -
Dielectric 3 Dielectric Core 0.1 FR-4 (R-1755M) 4.7
GND Signal Copper 0.036 -
Dielectric 4 Dielectric Prepreg 0.1 FR-4 (R-1755M) 4.6
Routing Signal Copper 0.036 -
Dielectric 5 Dielectric Core 0.25 FR-4 (R-1755M) 4.7
Bottom GND Signal Copper 0.043 -
Bottom solder Solder mask/Coverlay Surface 0.01016 Solder resist 4.5
Bottom overlay Overlay
PCB UM2742
38/44 UM2742 Rev 2
Figure 22. Top layer layout
UM2742 Rev 2 39/44
UM2742 PCB
43
Figure 23. RF GND layer (L2), GND layer (L4) and bottom layer (L6) layout
PCB UM2742
40/44 UM2742 Rev 2
Figure 24. Power layer (L3) layout
UM2742 Rev 2 41/44
UM2742 PCB
43
Figure 25. Routing layer (L5) layout
Electrical characteristics UM2742
42/44 UM2742 Rev 2
5 Electrical characteristics
Violating the values listed inTable 17 may damage the reader. Correct operation is not guaranteed when operating outside these specifications.
Table 17. Absolute maximum ratings
Operation temperature 0 °C to +55 °C
Storage temperature 30 °C to +85 °C
DC supply voltage +6.5 V
Table 18. DC characteristics (VBUS = 5.0 V, 25 °C)
Symbol Parameter Min Typ Max Unit
VBUS Supply voltage 4.5 5.0 5.5 V
IBUS Supply current 110 119 125
mAIPAext External PA current(1)
1. Default power setting.
735 840 945
IPAint Internal PA current(1) 325 353 385
UM2742 Rev 2 43/44
UM2742 Revision history
43
6 Revision history
Table 19. Document revision history
Date Revision Changes
10-Aug-2020 1 Initial release.
17-Nov-2020 2
Updated Section 1.1: Board features and Section 2.1: RF circuit.
Updated Table 11: Connection of components, Table 13: Supply voltages of analog test points and Table 18: DC characteristics (VBUS = 5.0 V, 25 °C).
UM2742
44/44 UM2742 Rev 2
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