RDM-A4FZ

RF Transceiver Module in 433 MHz

The RDM-A4FZ is a low power, highly integrated FSK/GFSK/ASK/OOK/GOOK transceiver designed for operation in the low UHF and VHF bands. The RDM-A4FZ uses an external VCO inductor that allows users to set the operating frequency anywhere between 400 to 440 MHz. Using the divide-by-2 circuit allows users to operate the device as low as 80 MHz. The typical range of the VCO is about 10% of the operating frequency. A complete transceiver can be built using a small number of external discrete components, making the RDM-A4FZ very suitable for price-sensitive and area-sensitive applications. The transmit section 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 transceiver RF frequency, channel spacing, and modulation are programmable using a simple 3-wire interface. The device 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.

Frequency of operation

• Standard 433 MHz but can support 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
• 111.8 dBm at 9.6 kbps, ASK

Supply Voltage

• 2.3 V to 3.6 V

Power Consumption

• In Receive mode: 18 mA
• In Transmit mode: 27 mA (at 10 dBm output)

RF Output Power

• Programmable output power from -20 dBm to +13 dBm in 63 steps

Data Rate

• 0.15 kbps to 200 kbps, FSK
• 0.15 kbps to 64 kbps, ASK

Modulation

• FSK, GFSK, ASK, OOK and GOOK modulations

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 tolerance crystals
• Digital RSSI
• Integrated TRx switch
• Leakage current <1 ìA in power-down mode

SMA Whip Antenna

4.1 x 3.2 x 0.5 (L x W x H) in cms