RFM22 (ISM Transceiver module)
The RFM22 is low cost ISM transceiver module and offers advanced radio features including continuous frequency coverage from 240–930 MHz and adjustable output power of up to +17 dBm. The extremely low receive sensitivity (–118 dBm) coupled with industry leading +17dBm output power ensures extended range and improved link performance. Support for frequency hopping can be used to further extend range and enhance performance. Additional system features such as an automatic wake-up timer, low battery detector, 64 byte TX/RX FIFOs, automatic packet handling, and preamble detection reduce overall current consumption and allow the use of lower-cost system MCUs. An integrated temperature sensor, general purpose ADC, power-on-reset (POR), and GPIOs further reduce overall system cost and size. The RFM22‘s digital receive architecture features a high-performance ADC and DSP based modem which performs demodulation, filtering, and packet handling for increased flexibility and performance. This digital architecture simplifies system design while allowing for the use of lower-end MCUs. The direct digital transmit modulation and automatic PA power ramping ensure precise transmit modulation and reduced spectral spreading ensuring compliance with FCC and ETSI regulations.