Overview

The RFM95W is a low-power, long-range wireless transceiver module manufactured by HopeRF. Powered by Semtech's SX1276 LoRa (Long Range) modem engine, it operates in the sub-GHz license-free ISM bands (868 MHz in Europe, 915 MHz in the Americas and Australia).

Using chirp spread spectrum (CSS) modulation, the RFM95W achieves receiver sensitivities down to -148 dBm and transmit power up to +20 dBm (100 mW100\text{ mW}). This enables point-to-point wireless ranges of several kilometers line-of-sight and integration into LoRaWAN IoT gateway networks.

Quick reference

Operating Voltage (VDD)1.8 V to 3.7 V DC (3.3 V nominal)
Logic Levels3.3 V TTL (requires level shifting for 5V MCUs)
Frequency Bands868 MHz (EU) / 915 MHz (US/AU)
RF Transmit Power+5 to +20 dBm (up to 100 mW software configurable)
Receiver SensitivityDown to -148 dBm
Communication Interface4-wire SPI (up to 10 MHz) + hardware DIO interrupt pins
Peak Transmit Current120 mA (+20 dBm output)
Receive Current10.3 mA
Sleep Current0.2 µA

Pinout

Standard 16-Pin Castellation Module Header

PinNameTypeDescription
1GNDPowerGround (0 V)
2MISODigital OutputSPI Master Input Slave Output
3MOSIDigital InputSPI Master Output Slave Input
4SCKDigital InputSPI Clock input
5NSS / CSDigital InputSPI Chip Select (Active-LOW)
6RESETDigital InputActive-LOW Reset input pin
7, 8, 9, 10, 11DIO0–DIO4Digital OutputConfigurable Digital I/O Interrupt pins (DIO0 = TxDone/RxDone)
12DIO5Digital OutputConfigurable ModeReady interrupt pin
133.3V / VDDPowerSupply voltage (+1.8 V to +3.7 V DC)
14GNDPowerGround
15ANA / ANTRF I/ORF Antenna connection point (50 Ω impedance)
16GNDPowerRF Ground shield

Specifications

ParameterSymbolMinTypMaxUnitConditions
Supply VoltageVDDV_{DD}1.83.33.7VDC
Transmit Current (+20dBm)ITXI_{TX}—120130mAPA_BOOST pin enabled
Transmit Current (+13dBm)ITX13I_{TX13}—2935mARFO pin enabled
Receive CurrentIRXI_{RX}—10.312.0mALoRa Mode, BW=125 kHzBW = 125\text{ kHz}
Spreading FactorSFSF6—12—Configurable (SF6 to SF12)
BandwidthBWBW7.8125500kHzConfigurable
Frequency ErrorΔf\Delta f-10—+10ppmCrystal accuracy

Spreading Factor (SF) vs Range Trade-off

Spreading FactorBit Rate (BW = 125 kHz)SensitivityAirtime (20-byte payload)Link Budget / Distance
SF75.47 kbps-123 dBm56 msShortest Range / Fast speed
SF91.76 kbps-129 dBm185 msMedium Range
SF120.29 kbps-137 dBm1482 msMaximum Range / Slow speed

Wiring

RFM95W Module / Breakout Pin→Microcontroller (Arduino / ESP32)Notes
VIN / 3.3V3.3VDo NOT connect to 5V!
GNDGNDGround
EN / RESETGPIO Pin (e.g. D9 / GPIO14)Reset control
G0 / DIO0GPIO Pin with Interrupt (e.g. D2 / GPIO26)Required for RxDone / TxDone events
SCKSPI SCK (D13 on Uno / GPIO18 on ESP32)SPI Clock
MISOSPI MISO (D12 on Uno / GPIO19 on ESP32)SPI Data Out
MOSISPI MOSI (D11 on Uno / GPIO23 on ESP32)SPI Data In
CS / NSSSPI SS / GPIO (D10 on Uno / GPIO5 on ESP32)Chip Select
Warning

Antenna Requirement Warning: NEVER power ON or transmit with an RFM95W module without a 50 Ω50\text{ }\Omega antenna (or a 8.2 cm8.2\text{ cm} wire for 868 MHz / 8.6 cm8.6\text{ cm} wire for 915 MHz) attached to the ANT pin. Transmitting without an antenna creates RF energy reflection that will permanently burn out the internal Power Amplifier (PA).

Common mistakes

  • Powering from 5.0V or connecting 5V SPI signals: The SX1276 silicon die is NOT 5V tolerant. Always use 3.3V supply and level shifters on 5V microcontrollers.
  • Forgetting DIO0 interrupt connection: Libraries like RadioHead or LMIC rely on hardware interrupts on DIO0 to signal packet reception. Leaving DIO0 disconnected will cause software wait timeouts.
  • Frequency mismatch: Operating an 868 MHz module on 915 MHz software settings degrades output power and range severely.

Notes

  • Compatible with popular open-source libraries like RadioHead (RH_RF95) and MCCI LoRaWAN LMIC framework.

Assets & downloads