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RBF Wireless Communication Chip

Product Model: RB4331/RB8681/RB9151​

Revision History

Rev.DateUpdate Description
1.02025-04-03New version release

1. Product Description​

1.1 Key Features​

  • Low Power Wireless System-on-Chip
  • Sub-GHz 433/868/915 MHz models are available
  • Integrated 39MHz & 32.768kHZ Clock
  • Fully integrated RF matching and Antenna
  • DC/DC converter with loading circuit
  • TX power up to +20 dBm
  • High Performance 32-bit 78 MHz ARM Cortex®-M33
  • 512 kB Flash program memory and 64 kB RAM data memory
  • 21 configurable GPIOs
  • Interfaces ADC, ACMP, VDAC, SPI, I2C, UART, PWM, PDM and other interface
  • Power supply 1.71 to 3.8V
  • Packaging: LGA 10 x 10 x 1.72 mm
  • Operating temperature range: -40 ºC to 85 ºC

image-20250403173257605

1.2 Product Feature Summary​

  • Low-power CE/RED certified chip with ultra-low energy consumption, enabling easy battery operation.
  • Communication range of up to 3.5 kilometers (in open space), supporting star and mesh network configurations with a capacity of up to 10,000 devices.
  • Utilizes advanced technologies such as FHSS, TDMA, and AES-CCM+ encryption for secure and reliable data transmission.
  • Low-code development with a packaged protocol stack and user-friendly API accelerates the production process.
  • OTA multicast technology allows simultaneous firmware updates to multiple devices.
  • High RF integration enables the use of external antennas, reducing the need for in-house development.
  • Low PCB layer count minimizes manufacturing costs.

image-20250403173146917

1.3 Typical Application​

  • Wireless Meter Reading System (Water meter, gas meter, heat meter, electricity meter, etc)
  • Wireless Security System in House/Villa, Office, Retail and other SMB scenarios
  • Electric Vehicles and Charging Points
  • Smart Apartment (Express Cabinet, Smart Lock, etc)
  • Industrial Automation

1.4 Block Diagram​

image-20250417134721280

2. Product Detail​

2.1 Component Layout, External Dimensions and Pad Design​

image-20250403173649440

image-20250403173658100

2.2 Mark Specification Range​

图片

CodeBxYYMMDD
ExplanationProduction batchYearMonthDay
Code - printingB1240627

Mark accuracy：20um~40um

Mark depth：±50um

2.3 Pin Definition​

image-20250403173858342

Pin numbersymbolIO typefunction
1GNDPChip power reference ground
2VCCPPower supply pins of the chip (typical supply voltage: 3.3V)
3PD3I/Ogeneral I/O （Configurable features）
4PD2I/Ogeneral I/O （Configurable features）
5GNDPChip power reference ground
6GNDPChip power reference ground
7PC0I/Ogeneral I/O （Configurable features）
8PC1I/Ogeneral I/O （Configurable features）
9PC2I/Ogeneral I/O （Configurable features）
10PC3I/Ogeneral I/O （Configurable features）
11PC4I/Ogeneral I/O （Configurable features）
12PC5I/Ogeneral I/O （Configurable features）
13PC6I/Ogeneral I/O （Configurable features）
14PC7I/Ogeneral I/O （Configurable features）
15RSTIChip hardware reset pin, default high level, effective when pulled low
16PB0I/Ogeneral I/O （Configurable features）
17PB1I/Ogeneral I/O （Configurable features）
18GNDPChip power reference ground
19ANTI/ORF transmitting and receiving pi
20PA0I/Ogeneral I/O （Configurable features）
21PA1I/Ogeneral I/O （Configurable features）
22PA2I/Ogeneral I/O （Configurable features）
23PA3I/Ogeneral I/O （Configurable features）
24PA4I/Ogeneral I/O （Configurable features）
25PA5I/Ogeneral I/O （Configurable features）
26PA6I/Ogeneral I/O （Configurable features）
27PA7I/Ogeneral I/O （Configurable features）
28PA8I/Ogeneral I/O （Configurable features）

​

GPIOAlternate Functions
PA00IADC0.VREFP
PA01GPIO.SWCLK
PA02GPIO.SWDIO
PA03GPIO.SWV，GPIO.TDO，GPIO.TRACEDATA0，LESENSE.EN_0
PA04GPIO.TDI，GPIO.TRACECLK，LESENSE.EN_1
PA05GPIO.TRACEDATA1，GPIO.EM4WU0，LESENSE.EN_2
PA06GPIO.TRACEDATA2
PA07GPIO.TRACEDATA3
PB00VDAC0.CH0_MAIN_OUT
PB01GPIO.EM4WU3，VDAC0.CH1_MAIN_OUT
GPIOAlternate Functions
PC0GPIO.EM4WU6
PC05GPIO.EM4WU7
PC0GPIO.EM4WU8，GPIO.THMSW_EN
PD02GPIO.EM4WU9

2.4 Topology & Usage​

image-20250403174327658

3. Specification​

3.1 Technical Specification​

ModelRB4331RB8681RB9151
Frequency Band433.12MHz~435.12MHz863 MHz ~ 870 MHz902 MHz ~ 928 MHz
Antenna OptionU.FL, RF padU.FL, RF padU.FL, RF pad
RAM64 KB64 KB64 KB
Flash512 KB512 KB512 KB
RF Data Rate2 kbps ~ 100 kbps2 kbps ~ 100 kbps2 kbps ~ 100 kbps
Transmit RangeUp to 3.5 km(Open Area)Up to 3.5 km(Open Area)Up to 3.5 km(Open Area)
Transmit PowerMax. 20dBmMax. 20dBmMax. 20dBm
Receiver ensitivity-110.7 dBm @50kbps(2GFSK)-113.3 dBm @38.4kbps(2GFSK)-96.9 dBm @2Mbps(2GFSK)
ModulationFSK / DSSSFSK / DSSSFSK / DSSS
Digital I/O21-ch Digital I/O21-ch Digital I/O21-ch Digital I/O
Analog Input21-ch Analog Inputs21-ch Analog Inputs21-ch Analog Inputs
Networking TopologyStarStarStar
EncryptionAES-CCM+Random Number KeyAES-CCM+Random Number KeyAES-CCM+Random Number Key
Image TransmitSupportSupportSupport
OTASupportSupportSupport
Supply Voltage1.7 V ~ 3.8V1.7 V ~ 3.8V1.7 V ~ 3.8V
Transmit CurrentMax 76.8 mA(20dBm)Max 90.6 mA(20dBm)Max 92 mA(20dBm)
Receive Current6.7@ (2-GFSK, 100kbps)6.3@ (2-GFSK, 38.4kbps)8.5@ (2-GFSK, 2 Mbps)
Sleep Current< 2 μA< 2 μA< 2 μA
Dimension10mm × 10mm × 1.72mm10mm × 10mm × 1.72mm10mm × 10mm × 1.72mm
Weight1.8g1.8g1.8g
Operating Temperature-40 °C ~ 85 °C-40 °C ~ 85 °C-40 °C ~ 85 °C
Storage Temperature-40℃ ~ 125℃-40℃ ~ 125℃-40℃ ~ 125℃
ETSI (Europe)CE/REDCE/REDCE/RED
RoHSCompliantCompliantCompliant

3.2 Absolute Maximum Ratings​

ParameterTest ConditionMinMaxUnit
Storage temperature range-50+150°C
Voltage on any supply pin-0.33.8V
Total current into VDD power linesSource-200mA
Total current into VSS ground linesSink-200mA
Current per I/O pinSink-50mA
Current per I/O pinSource-50mA
Current for all I/O pinsSink-200mA
Current for all I/O pinsSource-200mA

3.3 General Operating Conditions​

ParameterMinTypMaxUnit
Operating ambient tempera ture range-40-+85°C
VDD supply Voltage1.713.33.8V
IOVDD operating supply voltage1.713.33.8V

3.4 Power Consumption​

ParameterTest ConditionMinTypMaxUnit
Receive modef = 915 MHz, 2-GFSK, 2 Mbps-8.5-mA
Receive modef = 868 MHz, 2-GFSK, 38.4 kbps-6.3-mA
Receive modef = 433 MHz, 2-GFSK, 100 kbps-6.7-mA
Transmit mode ,EM1f = 915 MHz, CW, 20 dBm PA, +20 dBm output power-92-mA
Transmit mode ,EM1f = 869.5 MHz, CW, 20 dBm PA, +20 dBm output power-90.6-mA
Transmit mode ,EM1f = 433 MHz, CW, 20 dBm PA, +20 dBm output power-76.8-mA
Retained RAM bank in EM2 or EM3.-0.1-µA

3.5 Clock Sources​

Internal High Frequency Clock for RF Stability: 39 MHz Crystal Frequency Tolerance.

ParametersTest ConditionMinTypMaxUnit
Crystal frequency39MHz
Equivalent Series Resistance--30Ω
Load Capacitance12pF
Shunt Capacitance--3pF
Frequency ToleranceAt 25℃±3℃-8-8
Frequency StabilityOver Operating Temp.Range(Ref.to 25℃)-10-10ppm

Internal Low Frequency Clock for BLE Synchronization: 32.768 kHz Crystal Frequency Tolerance.

ParametersTest ConditionMinTypMaxUnit
Crystal frequency32.768000KHz
Equivalent Series Resistance-80KΩ
Load Capacitance12.5pF
Shunt Capacitance-1.15-pF
Frequency ToleranceAt 25℃±3℃-10-10

4. QA Requirement​

Information DescriptionStandard(Yes) Custom(No)
ESD TestingYes
RF Antenna AnalysisYes
Environmental TestingYes
Reliability TestingYes
CertificationFCC,CE, RoHS

5. Sub-GHz RF Transceiver Characteristics​

5.1 915 MHz Band +20 dBm RF Characteristics​

Conditions: 25ºC, VCC=3.3V, RF center frequency 915 MHz.

ParameterTest ConditionMinTypMaxUnit
RF test frequency range902-928MHz
Maximum TX PowerPAVDD = 3.3V, 20 dBm devices, +20 dBm match17.72021.4dBm
Minimum active TX Powe--20.6-dBm
Max usable input level, 0.1% BERDesired is reference 2 Mbps 2GFSK signal--10dBm
Sensitivity
Desired is reference 4.8 kbps OOK signal, PER<20%--113.1-dBm
Desired is reference 50 kbps 2FSK signal, Δf = ± 25 kHz, PER<10%--110.1-dBm
Desired is reference 50 kbps 2FSK signal, Δf = ± 25 kHz, PER--114.2-dBm
Desired is reference 150 kbps 2FSK signal, Δf = ± 37.5 kHz, PER<10%--107.5-dBm
Desired is reference 2 Mbps 2GFSK signal, Δf = ± 500 kHz, BER<0.1%--96.9-dBm
Desired is reference 4.8 kbps O QPSK signal, spreading factor=8, PER<1%--125.8-dBm
Desired is reference 250 kbps O QPSK DSSS signal, PER<1%--103.5-dBm
Desired is reference 120 kbps OOK signal8, PER<20%--102.6-dBm

5.2 868 MHz Band +20 dBm RF Characteristics​

Conditions: 25ºC, VCC=3.3V, RF center frequency 868 MHz.

ParameterTest ConditionMinTypMaxUnit
RF test frequency range868869.9MHz
Maximum TX PowerPAVDD = 3.3V, 20 dBm devices, +20 dBm match18.420.321.5dBm
Minimum active TX Powe--20.4-dBm
Max usable input level, 0.1% BERDesired is reference 500 kbps 2GMSK signal--10dBm
Sensitivity
Desired is reference 2.4 kbps 2GFSK signal, Δf = ± 1.2 kHz, BER<0.1%--125.3-dBm
Desired is reference 38.4 kbps 2GFSK signal, Δf = ± 20 kHz, BER<0.1%--113.3-dBm
Desired is reference 50 kbps 2FSK signal, Δf = ± 12.5 kHz, PER<10%--111.5-dBm
Desired is reference 100 kbps 2FSK signal, Δf = ± 25 kHz, PER<10%--109.2-dBm
Desired is reference 500 kbps 2GMSK signal, Δf = ± 125 kHz1, BER<0.1%--103.2-dBm
Desired is reference 100 kbps O QPSK DSSS signal, PER<1%---110.9-dBm

5.3 433 MHz Band +20 dBm RF Characteristics​

Conditions: 25ºC, VCC=3.3V, RF center frequency 433 MHz.

ParameterTest ConditionMinTypMaxUnit
RF test frequency range433.12434.72MHz
Maximum TX PowerPAVDD = 3.3V, 20 dBm devices, +20 dBm match17.619.821.1dBm
Minimum active TX Powe--20.3-dBm
Max usable input level, 0.1% BERDesired is reference 100 kbps 2GFSK signal, BER<0.1%l--10dBm
Sensitivity
Desired is reference 2.4 kbps 2GFSK signal, Δf = ± 1.2 kHz, BER<0.1%--126.9-dBm
Desired is reference 4.8 kbps OOK signal, PER<20%--114.2-dBm
Desired is reference 100 kbps 2GFSK signal, Δf = ± 50 kHz, BER<0.1%--110.7-dBm
Desired is reference 50 kbps 2GFSK signal, Δf = ± 25 kHz, BER<0.1%--113.8-dBm
Desired is reference 50 kbps 4GFSK signal, Δfo = ± 25 kHz, Δfi = ± 8.33 kHz, PER<1%--112.1-dBm
Desired is reference 460 MHz 4.8 kbps 2FSK signal, Δf = ± 2.4 kHz, PER<10%--122.5-dBm

6. Hardware Design Considerations​

  • The RBF chips of model 915/868/433 MHz have built-in RF chip matching circuits, eliminating the need for external placement of chip matching devices and saving board space.
  • The RBF chips of model 15/868/433MHZ have all integrated peripheral chips such as 39M crystal oscillator and 32.768K crystal oscillator.
  • The chip should not be placed in a casing made of metal. If a metal casing must be used, the antenna must be led out.
  • For the products that require installation of this chip, some metal components such as screws and inductors should be kept as far away as possible from the RF antenna part of the chip.
  • On the antenna of the chip, try not to place other components to avoid interference with the wireless performance.
  • The chip should be placed as close as possible to the edge or corner of the main board, and the PCB under the antenna part of the chip should be annotated and hollowed out with the keep out layer if it is not possible to hollow out. If copper plating or wiring is not allowed under the antenna, it will affect the RF performance.
  • Please pay attention to check the pin diagrams and the IO connected to them. Please pay attention to the IO mode and status.
  • GND must be well grounded.
  • It is recommended to use magnetic beads or inductors for filtering of the input power supply.

7. Antenna layout suggestion​

For RBF series chips, the internal integrated chip matching, customers only need to build an antenna matching circuit based on the external antenna.

For RBF series chip antenna design, it is recommended to reserve antenna matching devices. Because the RBF series chip frequency is 433MHz/868MHz/915MHz, the onboard antenna size is too large, it is not recommended to use the onboard antenna.

When using IPEX technology (external antenna), it is necessary to pay attention to the need for 50 Ohm matching in the RF output part, and it is recommended to cover the RF output part in the PCB layout by connecting holes to the ground to prevent unnecessary losses during the transmission of RF on the PCB board. And the RF part needs to be kept at a distance of more than 10mm from some interference sources, and the general layout needs to avoid any electrical components.

image-20250411132511745

8. Package Information​

ParameterValue
Packing TypeTape Reel
Packing Quantity100 pcs/ tape