Used in conjunction with EZRadio FSK receivers, the Si4022 is a flexible, low cost, and highly integrated solution that does not require production alignments. All required RF functions are integrated. Only an external crystal and bypass filtering are needed for operation.

The transmitter has a completely integrated PLL for easy RF design, and its rapid settling time allows for fast frequency-hopping, bypassing multipath fading and interference to achieve robust wireless links. The PLL's high resolution allows the usage of multiple channels in any of the bands. In addition, highly stable and accurate FSK modulation is accomplished by direct closed-loop modulation with bit rates up to 115.2 kbps.

The integrated power amplifier of the transmitter has an open-collector differential output and can directly drive a loop antenna with programmable output level, no additional matching network is required. An automatic antenna tuning circuit is built in to avoid both costly trimming procedures and de-tuning due to the "hand effect".

For battery-operated applications the device supports various power saving modes with wake-up interrupt generation options based on a low battery voltage detector and a sleep timer. Several additional features ease system design. Power-on reset and clock signals are provided to the microcontroller. An on-chip baud rate generator and a data FIFO are available. The transmitter is programmed and controlled via an SPI compatible interface.