Silicon Laboratories EFR32MG User manual
EFR32MG 2.4 GHz / 434 MHz Dual Band
10 dBm Radio Board
BRD4152A Reference Manual
The EFR32MG family of Wireless SoCs deliver a high performance, low energy wireless solution integrated into a small form
factor package.
By combining high performance sub-GHz RF and 2.4 GHz RF transceivers with an energy efficient 32-bit MCU, the family provides designers the ultimate in flexibility with a
family of pin-compatible devices that scale from 128/256 kB of flash and 16/32 kB of
RAM. The ultra-low power operating modes and fast wake-up times of the Silicon Labs
energy friendly 32-bit MCUs, combined with the low transmit and receive power consumption of the sub-GHz and 2.4 GHz radios result in a solution optimized for battery
powered applications.
To develop and/or evaluate the EFR32 Mighty Gecko the BRD4152A Radio Board can
be connected to the Wireless Starter Kit Mainboard to get access to display, buttons and
additional features from Expansion Boards.
RADIO BOARD FEATURES
• Wireless SoC:
EFR32MG1P232F256GM48
• CPU core: ARM Cortex-M4 with FPU
• Flash memory: 256 kB
• RAM: 32 kB
• Operation frequency: 2.4 GHz + 434 MHz
• Transmit power: 10 dBm
• Integrated PCB antenna, UFL connector
(optional).
• Crystals for LFXO and HFXO: 32.768 kHz
and 38.4 MHz.
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BRD4152A Reference Manual
Introduction
1. Introduction
The EFR32 Mighty Gecko Radio Boards provide a development platform (together with the Wireless Starter Kit Mainboard) for the
Silicon Labs EFR32 Mighty Gecko Wireless System on Chips and serve as reference designs for the matching networks of the RF interfaces.
The BRD4152A Radio Board supports dual-band operation with its integrated sub-GHz ISM band and 2.4 GHz band transceivers. The
sub-GHz section is designed to the operate in the European ETSI 433.05-434.79 MHz band with an external whip antenna, the 2.4 GHz
section is designed to operate at the 2400-2483.5 MHz band band with the on-board printed antenna. The matching networks are optimized to 10 dBm output power.
To develop and/or evaluate the EFR32 Mighty Gecko the BRD4152A Radio Board can be connected to the Wireless Starter Kit Mainboard to get access to display, buttons and additional features from Expansion Boards and also to evaluate the performance of the RF
interfaces.
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GND
F9 / PA3 / VCOM.#RTS_#CS
3v3
NC / P36
P200
Upper Row
NC / P38
NC / P40
NC / P42
NC / P44
DEBUG.TMS_SWDIO / PF1 / F0
DISP_ENABLE / PD15 / F14
UIF_BUTTON0 / PF6 / F12
UIF_LED0 / PF4 / F10
VCOM.#CTS_SCLK / PA2 / F8
DEBUG.RESET / RADIO_#RESET / F4
DEBUG.TDO_SWO / PF2 / F2
DISP_SI / PC6 / F16
VCOM.TX_MOSI / PA0 / F6
PTI.DATA / PB12 / F20
DISP_EXTCOMIN / PD13 / F18
USB_VBUS
5V
Board ID SCL
GND
Board ID SDA
USB_VREG
F7 / PA1 / VCOM.RX_MISO
F5 / PA5 / VCOM_ENABLE
F3 / PF3 / DEBUG.TDI
F1 / PF0 / DEBUG.TCK_SWCLK
P45 / NC
P43 / NC
P41 / NC
P39 / NC
P37 / PD15 / SENSOR_ENABLE
F11 / PF5 / UIF_LED1
F13 / PF7 / UIF_BUTTON1
F15 / PC8 / DISP_SCLK
F17 / PD14 / DISP_SCS
F19 / PB13 / PTI.SYNC
F21 / PB11 / PTI.CLK
GND
VMCU_IN
VCOM.#CTS_SCLK / PA2 / P0
P201
Lower Row
VCOM.#RTS_#CS / PA3 / P2
UIF_BUTTON0 / PF6 / P4
UIF_BUTTON1 / PF7 / P6
GND
VRF_IN
P35 / PD15 / DISP_ENABLE
P7 / PC9
P5 / PC8 / DISP_SCLK
P3 / PC7
P1 / PC6 / DISP_SI
P33 / PD14 / DISP_SCS
P31 / PD13 / DISP_EXTCOMIN
P29 / NC
P27 / NC
P25 / NC
P23 / NC
P21 / NC
P19 / NC
P17 / NC
P15 / NC
P13 / PC11
P11 / PA1 /VCOM.RX_MISO
P9 / PA0 / VCOM.TX_MOSI
NC / P34
UIF_LED1 / PF5 / P32
NC / P30
DEBUG.TDO_SWO / PF2 / P28
DEBUG.TMS_SWDIO / PF1 / P26
DEBUG.TMS_SWCLK / PF0 / P24
PTI.SYNC / PB13 / P22
PTI.DATA / PB12 / P20
PTI.CLK / PB11 / P18
VCOM_ENABLE / PA5 / P16
PA4 / P14
PC10 / P12
DEBUG.TDI / PF3 / P10
UIF_LED0 / PF4 / P8
BRD4152A Reference Manual
Radio Board Connector
2. Radio Board Connector
2.1 Introduction
The board-to-board connector scheme allows access to all EFR32MG1 GPIO pins as well as the RESETn signal. For more information
on the functions of the available pin functions, we refer you to the EFR32MG1 Datasheet.
2.2 Radio Board Connector Pin Associations
The figure below shows the pin mapping on the connector to the radio pins and their function on the Wireless Starter Kit Mainboard.
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Figure 2.1. BRD4152A Radio Board Connector Pin Mapping
3. Radio Board Block Summary
EFR32
Inverted-F
PCB
Antenna
2.4 GHz RF
UFL
Connector
LF
Crystal
32.768k
HF
Crystal
38.4M
Radio
Board
Connectors
8 Mbit
MX25R
Serial Flash
I2C
24AA0024
Serial EEPROM
Matching
Network &
Path
Selection
GPIO
UART
Debug
Packet Trace
AEM
I2C
SPI
SPI
2.4 GHz RF
2.4 GHz RF
SubGHz RF
Matching
Network &
DC Bias
SubGHz RF
SMA
Connector
EFR32
EFR32
Wireless SoC
3.1 Introduction
This section gives a short introduction to the blocks of the BRD4152A Radio Board.
3.2 Radio Board Block Diagram
The block diagram of the BRD4152A Radio Board is shown in the figure below.
BRD4152A Reference Manual
Radio Board Block Summary
Figure 3.1. BRD4152A Block Diagram
3.3 Radio Board Block Description
3.3.1 Wireless MCU
The BRD4152A EFR32 Mighty Gecko Radio Board incorporates an EFR32MG1P232F256GM48 Wireless System on Chip featuring
32-bit Cortex-M4 with FPU core, 256 kB of flash memory 32 kB of RAM, an integrated 2.4 GHz band and an integrated sub-GHz ISM
band transceiver with output power up to 19.5 dBm. For additional information on the EFR32MG1P232F256GM48, refer to the
EFR32MG1 Data Sheet.
3.3.2 LF Crystal Oscillator (LFXO)
The BRD4152A Radio Board has a 32.768 kHz crystal mounted.
3.3.3 HF Crystal Oscillator (HFXO)
The BRD4152A Radio Board has a 38.4 MHz crystal mounted.
3.3.4 Matching Network for Sub-GHz
The BRD4152A Radio Board incorporates a sub-GHz matching network which connects both the sub-GHz TX and RX pins of the
EFR32MG1 to the one SMA connector to be able to transmit and receive with one antenna. The component values were optimized for
the 434 MHz band RF performace and current consumption with 10 dBm output power.
For detailed description of the matching network see Chapter 4.2.1 Description of the Sub-GHz RF Matching.
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BRD4152A Reference Manual
Radio Board Block Summary
3.3.5 Matching Network for 2.4 GHz
The BRD4152A Radio Board incorporates a 2.4 GHz matching network which connects the 2.4 GHz TRX pin of the EFR32MG1 to the
one on-board printed Inverted-F antenna. The component values were optimized for the 2.4 GHz band RF performace and current consumption with 10 dBm output power.
For detailed description of the matching network see Chapter 4.2.2 Description of the 2.4 GHz RF Matching.
3.3.6 Inverted-F Antenna
The BRD4152A Radio Board includes a printed Inverted-F antenna (IFA) tuned to have close to 50 Ohm impedance at the 2.4 GHz
band.
For detailed description of the antenna see Chapter 4.6 Inverted-F Antenna.
3.3.7 SMA connector
To be able to perform conducted measurements or mount external antenna for radiated measurements, range tests etc., Silicon Labs
added an SMA connector to the Radio Board. The connector allows an external 50 Ohm cable or antenna to be connected during design verification or testing.
3.3.8 UFL Connector
To be able to perform conducted measurements Silicon Labs added an UFL connector to the Radio Board. The connector allows an
external 50 Ohm cable or antenna to be connected during design verification or testing.
Note: By default the output of the matching network is connected to the printed Inverted-F antenna by a series component. It can be
connected to the UFL connector as well through a series 0 Ohm resistor which is not mounted by default. For conducted measurements
through the UFL connector the series component to the antenna should be removed and the 0 Ohm resistor should be mounted (see
Chapter 4.2 Schematic of the RF Matching Network for further details).
3.3.9 Radio Board Connectors
Two dual-row, 0.05” pitch polarized connectors make up the BRD4152A Radio Board interface to the Wireless Starter Kit Mainboard.
For more information on the pin mapping between the EFR32MG1P232F256GM48 and the Radio Board Connector refer to Chapter
2.2 Radio Board Connector Pin Associations.
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4. RF Section
GND
VBIAS
GND
GND
GND
GND
C10
C13
C3
L1
C11
L4
AT1
INVERTED_F
C4
Ground
RF I/ORF Crystal
RF Analog Power
PA Power
U1B
EFR32
2G4RF_IOP
20
2G4RF_ION
19
RFVDD
9
HFXI
10
HFXO
11
PAVDD
21
RFVSS
17
PAVSS
18
SUBGRF_OP
13
SUBGRF_ON
14
SUBGRF_IP
15
SUBGRF_IN
16
C12
C1
C8
R1
0R
C9
P2
U.FL
3
2
1
L7
L5
L8
TP1
C6
L6
P1
SMA
3
2
1
4
5
L9
C5
R2
0R
NM
L3
BAL1
ATB2012-50011
14
3 2
C7
2.4 GHz Matching Network
Sub-GHz Matching Network
TRX Matching
Filter
Antenna
Connector
Inverted-F
Antenna
Test
Connector
TRX Matching
Discrete Balun
Path Selection
GND
GND
GND
VDCDC
VDCDC
GND
VBIAS
X1
38.400 MHz
31
2
4
C107
10P
L102
BLM18AG601SN1
1 2
L103
BLM18AG601SN1
1 2
C102
100P
C103
10P
C106
220N
Supply Filtering
High Frequency
Crystal
Sub-GHz PA
Power Supply
4.1 Introduction
This section gives a short introduction to the RF section of the BRD4152A.
4.2 Schematic of the RF Matching Network
The schematic of the RF section of the BRD4152A Radio Board is shown in the following figure.
BRD4152A Reference Manual
RF Section
Figure 4.1. Schematic of the RF Section of the BRD4152A
4.2.1 Description of the Sub-GHz RF Matching
The sub-GHz matching network connects the differential TX outputs and RX inputs of the sub-GHz RF port to the SMA connector while
transforming the impedances to 50 Ohm. Careful design procedure was followed to ensure that the RX input circuitry does not load
down the TX output path while in TX mode and that the TX output circuitry does not degrade receive performance while in RX mode.
The matching includes a differential impedance matching circuitry, a discrete balanced-unbalanced transformer and a filter section. The
targeted output power is 10 dBm at 434 MHz.
4.2.2 Description of the 2.4 GHz RF Matching
The 2.4 GHz matching connects the RFIO_P pin to the on-board printed Inverted-F Antenna. The RFIO_N pin is connected to ground.
For lower output powers (under 13 dBm) additional harmonic filtering is not required as the harmonic levels are below the regulation
limits (see Chapter 7.1.2 Conducted Measurements in the 2.4 GHz band). Thus the matching network comprises only a two-element
impedance matching circuitry. The targeted output power is 10 dBm.
For conducted measurements the output of the matching network can also be connected to the UFL connector by relocating the series
R1 0 Ohm resistor to the R2 position between the output of the matching and the UFL connector.
4.3 RF Section Power Supply
On the BRD4152A Radio Board the supply for the radio (RFVDD) and the power amplifiers (VBIAS) is connected to the on-chip DC-DC
converter. This way, by default, the DC-DC converter provides 1.8 V for the entire RF section (for details, see the schematic of the
BRD4152A).
4.4 Bill of Materials for the sub-GHz Matching
The Bill of Materials of the sub-GHz matching network of the BRD4152A Radio Board is shown in the following table.
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BRD4152A Reference Manual
RF Section
Table 4.1. Bill of Materials for the BRD4152A 434 MHz 10 dBm RF Matching Network
Component name Value Manufacturer Part Number
BAL1 Balun TDK Corporation ATB2012-50011
C3 1.6 pF Murata GRM1555C1H1R6WA01
C4 1.6 pF Murata GRM1555C1H1R6WA01
C5 Not mounted - -
C6 Not mounted - -
C7 4.7 pF Murata GRM1555C1H4R7WA01
C8 270 pF Murata GRM1555C1H271FA01
C9 270 pF Murata GRM1555C1H271FA01
C10 6.2 pF Murata GRM1555C1H6R2BA01
C11 11 pF Murata GRM1555C1H110GA01
C12 5.6 pF Murata GRM1555C1H5R6WA01
C13 270 pF Murata GRM1555C1H271FA01
L3 75 nH Murata LQW18AN75NG00
L4 470 nH Murata LQW18CNR47J00
L5 470 nH Murata LQW18CNR47J00
L6 18 nH Murata LQW15AN18NG00
L7 18 nH Murata LQW15AN18NG00
L8 24 nH Murata LQW15AN24NG00
L9 24 nH Murata LQW15AN24NG00
4.5 Bill of Materials for the 2.4 GHz Matching
The Bill of Materials of the 2.4 GHz matching network of the BRD4152A Radio Board is shown in the following table.
Table 4.2. Bill of Materials for the BRD4152A 2.4 GHz 10 dBm RF Matching Network
Component name Value Manufacturer Part Number
C1 2.0 pF Murata GRM1555C1H2R0WA01
C2 1.0 pF Murata GRM1555C1H1R0WA01
L1 1.8 nH Murata LQP15MN1N8W02
L2 3.0 nH Murata LQP15MN3N0W02
4.6 Inverted-F Antenna
The BRD4152A Radio Board includes an on-board printed Inverted-F Antenna tuned for the 2.4 GHz band. Due to the design restrictions of the Radio Board the input of the antenna and the output of the matching network can't be placed directly next to each other thus
a 50 Ohm transmission line was necessary to connect them. The resulting impedance and reflection measured at the output of the
matcing network are shown in the following figure. As it can be observed the impedance is close to 50 Ohm (the reflection is better than
-10 dB) for the entire 2.4 GHz band.
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