RF-Star RF-BM-BG22A3 User manual

RF-BM-BG22A3(I) EFR32BG22C224
Bluetooth 5.2 Low Energy Module
Version 1.3
Shenzhen RF-star Technology Co., Ltd.
August 12th, 2022

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1 Device Overview
1.1 Module Series
There is a series of RF-BM-BG22Ax Bluetooth 5.2 Low Energy modules. All of them are based on Silicon Labs
EFR32BG22 SoC series. Because the EFR32BG22 series ICs are compatible in package, pins, and peripherals, those
modules are pin-to-pin compatible with each other as well.
Table 1. Module Series of RF-BM-BG22Ax
Model
Chip Model
Max. CPU
Speed
TX
Power
FLASH
RAM
Protocol
BG22A1
EFR32BG22C112F352GM32-C
38.4 MHz
0 dBm
352 KB
32 KB
BT5.2
BG22A1I
EFR32BG22C112F352GM32-C
38.4 MHz
0 dBm
352 KB
32 KB
BT5.2
BG22A3
EFR32BG22C224F512GM32-C
76.8 MHz
+6 dBm
512 KB
32 KB
BT5.2
Direction finding
Proprietary
BG22A3I
EFR32BG22C224F512GM32-C
76.8 MHz
+6 dBm
512 KB
32 KB
BT5.2
Direction finding
Proprietary
Note: RF-BM-BG22A1 and RF-BM-BG22A1I do not support AoA/AoD and LE Long Range (125 Kbps and 500 Kbps)
PHYs.
1.2 Description
RF-BM-BG22A3(I) is an RF module based on EFR32BG22C224F512GM32-C, one of the Gecko family of SoCs from
Silicon Labs, with a 32-bit ARM® Cortex®-M33 core with 76.8 MHz maximum operating frequency. It integrates a 38.4
MHz crystal, a matching, an antenna matching, a low-pass filter, and the antenna option (the one is a meander line
inverted-F PCB antenna and a half-hole ANT pin, and the other is the IPEX connector and a half-hole ANT pin). As for
the hardware, it supports Bluetooth 5.2 Low Energy, Low Power Node of Bluetooth Mesh, Direction Finding AoA/AoD
and proprietary and also has a range of analog and digital interfaces such as PRS, ADC, UART, SPI, I2C, PWM, ISO
7816, IrDA, I2S, EUART and PDM. It features low power consumption, compact size, robust connection distance, and
rigid reliability. An integrated PA in the chip enables the module to reach up to 6 dBm TX power. 1.27-mm pitch stamp
stick package for easy assembling and cost-effective PCB design. As for the firmware, it can be preprogrammed with
an RF-star BLE5.0 serial communication protocol for simple programming.
1.3 Key Features
•RF Features
- Bluetooth 5.2 Low Energy
- Bluetooth Mesh Low Power Node
- Direction finding using Angle-of-Arrival (AoA) and
Angle-of-Departure (AoD)
- Proprietary
•Modulation
- 2 (G)FSK with fully configurable shaping
- OQPSK DSSS
- (G)MSK

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•TX power: -28 dBm ~ 6 dBm
•Sensitivity
- -98.9 dBm @ 1 Mbit/s GFSK
- -96.2 dBm @ 2 Mbit/s GFSK
- -106.7 dBm @ 125 kbit/s GFSK
•32-bit 76.8 MHz ARM® Cortex®-M33 with DSP
instruction and floating-point unit for efficient signal
processing
•Memory
- Flash: 512 KB
- RAM: 32 KB
•Wide Operation Range
- Single power supply
⬧DC-DC mode: 2.2 V to 3.8 V
⬧Bypass mode: 1.8 V to 3.8 V
- Operating temperature: -40 °C to +85 °C
- Storage temperature: -40 °C to +125 °C
•Wide Peripherals
- 12-bit 1 Msps SAR ADC
- Up to 18 GPIOs with output state retention and
asynchronous interrupts
- 8 Channel DMA Controller
- 12 Channel Peripheral Reflex System (PRS)
- 4×16-bit Timer/Counter with 3
Compare/Capture/PWM channels
- 1×32-bit Timer/Counter with 3
Compare/Capture/PWM channels
- 32-bit RTC
- 24-bit Low Energy Timer for waveform generation
- 1×Watchdog Timer
- 2×Universal Synchronous/Asynchronous
Receiver/Transmitter
⬧UART
⬧SPI
⬧SmartCard (ISO 7816)
⬧IrDA
⬧I2S
- 1×Enhanced Universal Asynchronous Receiver /
Transmitter (EUART)
- 2×I2C interface with SMBus support
- Digital microphone interface (PDM)
- Precision Low-Frequency RC Oscillator enabling
single-crystal operation
- RFSENSE with selective OOK mode
- Die temperature sensor with +/-2 degree C
accuracy across temperature range
•Security Features
- Secure Boot with Root of Trust and Secure Loader
(RTSL)
- Hardware Cryptographic Acceleration for
AES128/256, SHA-1, SHA-2 (up to 256-bit), ECC
(up to 256-bit), ECDSA, and ECDH
- True Random Number Generator (TRNG) compliant
with NIST SP800-90 and AIS-31
- ARM® TrustZone®
- Secure Debug with lock / unlock
•Transmission range:
- RF-BM-BG22A3: 110 m (@ PCB antenna, 1
Mbps/s); 135 m (@ PCB antenna, 125 kbps/s)
- RF-BM-BG22A3I: 155 m (@ external PCB antenna,
1 Mbps/s); 210 m (@ external PCB antenna, 125
kbps/s)
•Dimension: 16.5 mm x 11.6 mm x 2.06 mm
1.4 Applications
•Asset tags and beacons
•Consumer electronics remote controls
•Portable medical
•Sports, fitness and wellness devices
•Connected home
•Building automation and security

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1.5 Functional Block Diagram
Figure 1. Functional Block Diagram of RF-BM-BG22A3(I)
1.6 Part Number Conventions
The part numbers are of the form of RF-BM-BG22A3(I) where the fields are defined as follows:
Figure 2. Part Number Conventions of RF-BM-BG22A3(I)
EFR32
BG22
GPIOs
Debug
Reset
Low-Pass
Filter
Power Supply
DC-DC mode: 2.2 V to 3.8 V
Bypass mode: 1.8 V to 3.8 V
Antenna
Matching
38.4 MHz
Matching
Half-Hole
ANT Pin
PCB Antenna /
IPEX Connetor
Antenna
Switch
RF
BM
BG22
Company Name
RF-STAR
Wireless Type
Bluetooth Module
Chipset
EFR32BG22 Series
-
-
A
Module Version
The A HW Version
3
IC Code
EFR32BG22C224
I
Antenna Type
I: IPEX Connector

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Table of Contents
1 Device Overview............................................................................................................................................................. 1
1.1 Module Series ..................................................................................................................................................... 1
1.2 Description............................................................................................................................................................ 1
1.3 Key Features ....................................................................................................................................................... 1
1.4 Applications.......................................................................................................................................................... 2
1.5 Functional Block Diagram .............................................................................................................................. 3
1.6 Part Number Conventions.............................................................................................................................. 3
Table of Contents................................................................................................................................................................ 4
Table of Figures................................................................................................................................................................... 5
Table of Tables..................................................................................................................................................................... 5
2 Module Configuration and Functions ...................................................................................................................... 7
2.1 Module Parameters........................................................................................................................................... 7
2.2 Module Pin Diagram ......................................................................................................................................... 8
2.3 Pin Functions....................................................................................................................................................... 8
3 Specifications .................................................................................................................................................................10
3.1 Recommended Operating Conditions .....................................................................................................10
3.2 Handling Ratings..............................................................................................................................................10
3.3 Current Consumption .....................................................................................................................................10
4 Setting of Frequency Offset Register....................................................................................................................12
5 Application, Implementation, and Layout.............................................................................................................14
5.1 Module Photos..................................................................................................................................................14
5.2 Recommended PCB Footprint....................................................................................................................14
5.3 Schematic Diagram.........................................................................................................................................15
5.4 Antenna................................................................................................................................................................16
5.4.1 Antenna Design Recommendation ..............................................................................................16
5.4.2 Antenna Output Mode Modification..............................................................................................16
5.4.3 External Antenna Design Recommendation of the Half-Hole ANT Pin..........................17
5.4.4 IPEX Connector Specification........................................................................................................19
5.5 Basic Operation of Hardware Design ......................................................................................................20
5.6 Trouble Shooting..............................................................................................................................................20

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5.6.1 Unsatisfactory Transmission Distance........................................................................................20
5.6.2 Vulnerable Module..............................................................................................................................21
5.6.3 High Bit Error Rate .............................................................................................................................21
5.7 Electrostatics Discharge Warnings ...........................................................................................................21
5.8 Soldering and Reflow Condition.................................................................................................................21
5.9 Optional Package Specification .................................................................................................................23
6 Revision History ............................................................................................................................................................25
7 Contact Us.......................................................................................................................................................................26
Table of Figures
Figure 1. Functional Block Diagram of RF-BM-BG22A3(I) ....................................................................... 3
Figure 2. Part Number Conventions of RF-BM-BG22A3(I)....................................................................... 3
Figure 3. Pin Diagram of RF-BM-BG22A3(I).................................................................................................. 8
Figure 4. Photos of RF-BM-BG22A3(I)...........................................................................................................14
Figure 5. Recommended PCB Footprint of RF-BM-BG22A3(I) (mm) ................................................15
Figure 6. Schematic Diagram of RF-BM-BG22A3(I) .................................................................................15
Figure 7. Recommendation of Antenna Layout ...........................................................................................16
Figure 8. Antenna Output Mode Change of RF-BM-BG22A1................................................................17
Figure 9. Antenna Output Mode Change of RF-BM-BG22A1I...............................................................17
Figure 10. Reference Design of the External Antenna .............................................................................17
Figure 11. Reference Design of the External Antenna Traces...............................................................18
Figure 12. SI9000 Impedance Calculation Diagram..................................................................................18
Figure 13. Specification of Antenna Seat.......................................................................................................19
Figure 14. Specification of IPEX Wire .............................................................................................................19
Figure 15. Recommended Reflow for Lead-Free Solder.........................................................................22
Figure 16. Default Package by Tray.................................................................................................................23
Figure 17. Package by Tape & Reel ................................................................................................................24
Table of Tables
Table 1. Module Series of RF-BM-BG22Ax .................................................................................................... 1
Table 2. Parameters of RF-BM-BG22A3(I) ..................................................................................................... 7

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Table 3. Pin Functions of RF-BM-BG22A3(I) ................................................................................................. 8
Table 4. Recommended Operating Conditions of RF-BM-BG22A3(I) ................................................10
Table 5. Handling Ratings of RF-BM-BG22A3(I) ........................................................................................10
Table 6. Current Consumption of RF-BM-BG22A3(I)................................................................................10
Table 7. Temperature Table of Soldering and Reflow................................................................................22

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2 Module Configuration and Functions
2.1 Module Parameters
Table 2. Parameters of RF-BM-BG22A3(I)
Chipset
EFR32BG22C224F512GM32-C
Supply Power Voltage
DC-DC mode: 2.2 V ~ 3.8 V, recommended to 3.3 V
Bypass mode: 1.8 V ~ 3.8 V, recommended to 3.3 V
Frequency
2402 MHz ~ 2480 MHz
Transmit Power
-28.0 dBm ~ 6 dBm (typical: 0 dBm)
Receiving Sensitivity
-98.9 dBm sensitivity @ 1 Mbit/s GFSK
-96.2 dBm sensitivity @ 2 Mbit/s GFSK
-106.7 dBm sensitivity @ 125 kbps GFSK
GPIO
18
Crystal
38.4 MHz
RAM
32 KB
Flash
512 KB
Package
SMT Packaging (1.27-mm half-hole pitch stamp stick)
Frequency Error
±24 kHz
Dimension
16.5 mm x 11.6 mm x 2.06 mm
Type of Antenna
RF-BM-BG22A1: PCB antenna, half-hole ANT pin
RF-BM-BG22A1I: IPEX connector, half-hole ANT pin
Transmission Range in Open Air
RF-BM-BG22A3: 110 m (@ PCB antenna, 1 Mbps/s); 135 m (@ PCB antenna,
125 kbps/s)
RF-BM-BG22A3I: 155 m (@ external PCB antenna, 1 Mbps/s); 210 m (@
external PCB antenna, 125 kbps/s)
Operating Temperature
-40 ℃ ～ +85 ℃
Storage Temperature
-40 ℃ ～ +125 ℃

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2.2 Module Pin Diagram
RF-BM-BG22A1 RF-BM-BG22A1I
Figure 3. Pin Diagram of RF-BM-BG22A3(I)
2.3 Pin Functions
Table 3. Pin Functions of RF-BM-BG22A3(I)
Pin
Name
Chip Pin
Pin Type
Description
1
EXT_ANT
-
-
External antenna pin.
2
PB02
PB02
I/O
GPIO
3
PB01
PB01
I/O
GPIO
4
PB00
PB00
I/O
GPIO
5
PA00
PA00
-
GPIO
6
PA03
PA03
I/O
GPIO
7
PA04
PA04
I/O
GPIO
8
PA05
PA05
I/O
GPIO
9
PA06
PA06
I/O
GPIO
10
GND
GND
-
Ground

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11
RESET
RESET
-
Reset, active low, internal pull-up. The max. power
supply of this pin is 1.8 V under DC-DC mode.
12
PA01
PA01
I/O
GPIO/SWCLK (connect j-link)
13
PA02
PA02
I/O
GPIO/SWDIO (connect j-link)
14
GND
GND
-
Ground
15
VCC
VCC
VCC
2.2 V ~ 3.8 V, recommended to 3.3 V
16
PD01
PD01
I/O
GPIO
17
PD00
PD00
I/O
GPIO
18
PC00
PC00
I/O
GPIO
19
PC01
PC01
I/O
GPIO
20
PC02
PC02
I/O
GPIO
21
PC03
PC03
I/O
GPIO
22
PC04
PC04
I/O
GPIO
23
PC05
PC05
I/O
GPIO
24
GND
GND
-
Ground

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3 Specifications
3.1 Recommended Operating Conditions
The functional operation does not guarantee performance beyond the limits of the conditional parameter values in the
table below. Long-term work beyond this limit will affect the reliability of the module more or less.
Table 4. Recommended Operating Conditions of RF-BM-BG22A3(I)
Items
Condition
Min.
Typ.
Max.
Unit
Operating Supply Voltage
DC-DC mode
2.2
3.3
3.8
V
Bypass mode
1.8
3.3
3.8
V
Frequency Range
2402
2480
MHz
Operating Temperature
/
-40
+25
+85
℃
Environmental Hot Pendulum
/
-20
+20
℃/min
3.2 Handling Ratings
All measurements are based on the Silicon Labs reference design and datasheet.
Table 5. Handling Ratings of RF-BM-BG22A3(I)
Items
Condition
Min.
Typ.
Max.
Unit
Storage Temperature
Tstg
-40
+25
+125
℃
Human Body Model
HBM
±2000
V
Moisture Sensitivity Level
2
Charged Device Model
±500
V
3.3 Current Consumption
Table 6. Current Consumption of RF-BM-BG22A3(I)
Hardware Version: 1.0a
Test Date
May 14th, 2020
Test Condition
FLUKE15B+ multimeter, load connects to DSA1030 spectrum analyzer, offset: 0.2,
RBW = 100 KHz
Stand-by
1 A
Transmitting Current
Set Tx Power
Actual Tx Power
Actual Current
0 dBm
-0.5 dBm
4.0 mA
Receiving Current
2.5 mA

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Note: The test method is closely related to the current. For example, the output load antenna is different from the
standard 50 Ω test data.

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4 Setting of Frequency Offset Register
The setting of the frequency offset register can be regarded as the auxiliary setting of modifying the frequency offset for
the hardware RF part.
If the frequency offset is needed to be modified, you can find the sl_device_init_hfxo_config.h file in the corresponding
project and modify the CTUNE value.
Take the empty_RGB project as an example:
Oen the project, find the Project Explorer window, and open the project folder, as shown in the following figure.
Then choose the config folder, find the sl_device_init_hfxo_config.h file, and double-click to open it, as shown in the
figure below.

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Find SL_DEVICE_INIT_HFXO_CTUNE, the official default value of SiliconLabs is 140, RF-star changes it to 72
according to the requirements of the development board hardware RF part.
Remark: This is the value for RF-star’s standard EFR32BG22 series modules, the value of the other customized products
needs to be confirmed.
If the user needs to change to other values, you can directly modify it (Value range: 0 ~ 255). As shown below.

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5 Application, Implementation, and Layout
5.1 Module Photos
RF-BM-BG22A3 RF-BM-BG22A3I
Figure 4. Photos of RF-BM-BG22A3(I)
5.2 Recommended PCB Footprint
RF-BM-BG22A1

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RF-BM-BG22A1I
Figure 5. Recommended PCB Footprint of RF-BM-BG22A3(I) (mm)
5.3 Schematic Diagram
Figure 6. Schematic Diagram of RF-BM-BG22A3(I)

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5.4 Antenna
5.4.1 Antenna Design Recommendation
1. The antenna installation structure has a great influence on the module performance. It is necessary to ensure the
antenna is exposed and preferably vertically upward. When the module is installed inside of the case, a high-quality
antenna extension wire can be used to extend the antenna to the outside of the case.
2. The antenna must not be installed inside the metal case, which will cause the transmission distance to be greatly
weakened.
3. The recommendation of antenna layout.
The inverted-F antenna position on PCB is free-space electromagnetic radiation. The location and layout of the
antenna are key factors to increase the data rate and transmission range.
Therefore, the layout of the module antenna location and routing is recommended as follows:
（1）Place the antenna on the edge (corner) of the PCB.
（2）Make sure that there is no signal line or copper foil in each layer below the antenna.
（3）It is best to hollow out the antenna position in the following figure to ensure that the S11 of the module is
minimally affected.
Figure 7. Recommendation of Antenna Layout
Note: The hollow-out position is based on the antenna used.
5.4.2 Antenna Output Mode Modification
1. RF-BM-BG22A3 has two antenna output modes. The one is an onboard PCB antenna and the other is a stamp half-
hole output (ANT pin, see pin function table for details).

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The default delivery is the onboard PCB antenna, and R1 (0 Ω) is well welded. If you want to use the external
antenna by the ANT pin, pls disconnect the R1. The location of R1 is shown in the figure below.
Figure 8. Antenna Output Mode Change of RF-BM-BG22A1
2. RF-BM-BG22A3I has two antenna output modes. The one is an IPEX connector and the other is a stamp half-hole
output (ANT pin, see pin function table for details).
The default delivery is the IPEX connector, and the capacitor connected to the IPEX is welded. If you want to use
the external antenna by the ANT pin, the capacitor position should be removed to the left solder joint to have the access
to the ANT pin. The location of the capacitor is shown in the figure below.
Figure 9. Antenna Output Mode Change of RF-BM-BG22A1I
5.4.3 External Antenna Design Recommendation of the Half-Hole ANT Pin
1. A Π-type matching circuit is reserved for the antenna, and 50 Ω impedance control is performed on the RF traces.
The traces are as short as possible, and 135° or arc traces are used as much as possible. No vias are used to
change layers. More GND vias are placed around the RF traces.
Figure 10. Reference Design of the External Antenna

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Figure 11. Reference Design of the External Antenna Traces
2. The RF trace width and copper-clad spacing can be calculated by SI9000 software, and the impedance is controlled
to 50 Ω according to the actual board thickness, number of layers, plate, dielectric thickness, dielectric constant,
copper thickness, line width, line spacing, and solder mask thickness.
Example: FR4 is a double-layer board with a thickness of 1.0 mm. Through calculation, the width of the trace is
0.8254 mm, and the spacing between traces and copper is 0.22 mm.
Figure 12. SI9000 Impedance Calculation Diagram

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5.4.4 IPEX Connector Specification
RF-BM-BG22A3I module is integrated the IPEX version 1 antenna seat, the specification of the antenna seat is as
follows:
Figure 13. Specification of Antenna Seat
The specification of the IPEX wire end is as follows:
Figure 14. Specification of IPEX Wire