RF Transceiver Module in 433 MHz
The RDM-A4FZ is a low power, highly integrated FSK/GFSK/ASK/OOK/GOOK RF designed for operation in the low



UHF and VHF bands. The RDM-A4FZ UHF transceiver module and VHF transceiver module uses an external VCO inductor that allows users to set the operating frequency anywhere between 400 to 440 MHz. The transmit section in these UHF band transceiver modules contains a VCO and low noise fractional-N PLL with output resolution of <1 ppm. This frequency agile PLL allows the RDM-A4FZ to be used in frequency-hopping spread spectrum (FHSS) systems.

The VCO operates at twice the fundamental frequency to reduce spurious emissions and frequency pulling problems. The transmitter output power is programmable in 63 steps from −20 dBm to +13 dBm. The UHF transceiver module RF frequency, channel spacing, and modulation are programmable using a simple 3-wire interface. The RF transceiver module operates with a power supply range of 2.3 V to 3.6V and can be powered down when not in use. A low IF architecture is used in the receiver (200 kHz), minimizing power consumption and the external component count and avoiding interference problems at low frequencies.
The RDM-A4FZ supports a wide variety of programmable features, including Rx linearity, sensitivity, and IF bandwidth, allowing the user to trade off receiver sensitivity and selectivity for current consumption, depending on the application. The receiver also features automatic frequency control (AFC) loop, allowing the PLL to compensate for frequency error in the incoming signal. An on-chip ADC provides read back of an integrated temperature sensor, an external analog input, the battery voltage, or the RSSI signal, which provides savings on an ADC in some applications. The temperature sensor is accurate to ±10°C over the full operating temperature range of −40°C to +85°C. This accuracy can be improved by doing a 1-point calibration at room temperature and storing the result in memory.


  • Low cost wireless data transfer
  • Wireless medical applications
  • Remote control / security systems
  • Wireless sensor networks
  • Keyless entry
  • Home automation
  • Process and building control
  • Automotive systems
  • Active RFID solutions
  • AMR – Automated Meter Reading

Parameters Value
Part Number RDM-A4FZ
Frequency 400 MHz to 440 MHz
Interface Single board transceiver with SPI Interface
Receiver Sensitivity −119 dBm at 1 kbps, FSK.
  −114 dBm at 9.6 kbps, FSK
  −114 dBm at 9.6 kbps, FSK
Supply Voltage 2.3 V to 3.6 V
Power Consumption In Receive mode: 18 mA
  In Transmit mode: 22 mA (at 10 dBm output)
RF Output Power Programmable output power from -20 dBm to +13 dBm in 63 steps
Data Rate 1.2 kbps to 19.2 kbps
Modulation FSK, GFSK, ASK, OOK and GOOK
Antenna Options SMA Whip Antenna
Dimension 40.34 x 31.72 (L x W) in mm
Weight 5 gms
Operating Temperature -40° to +85° C
Compliance FCC: Yes
IC: Yes
Europe/ETSI: Yes
RoHS: Yes
Other Features On-chip VCO and fractional-N PLL
  On-chip 7-bit ADC and temperature sensor
  Fully automatic frequency control loop (AFC) compensates for lower
Data Sheet Download
Application Note Download
Sample Code Download