SI4421 Datasheet | Silicon Labs

Si4421 Universal ISM Band FSK Transceiver DESCRIPTION Silicon Labs’ Si4421 is a single chip, low power, multi-channel FSK transceiver designed for use in applications requiring FCC or ETSI conformance for unlicensed use in the 433, 868 and 915 MHz bands. The Si4421 transceiver is a part of Silicon Labs’ EZRadio TM product line, which produces a flexible, low cost, and highly integrated solution that does not require production alignments. The chip is a plete analog RF and baseband transceiver including a multi-band PLL synthesizer with PA, LNA, I/Q down converter mixers, baseband filters and amplifiers, and an I/Q demodulator. All required RF functions are integrated. Only an external crystal and bypass filtering are needed for operation. The Si4421 Features a pletely 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. The receiver baseband bandwidth (BW) is programmable to acmodate various deviation, data rate and crystal tolerance requirements. The transceiver employs the Zero-IF approach with I/Q demodulation. Consequently, no external ponents (except crystal and decoupling) are needed in most applications. The Si4421 dramatically reduces the load on the microcontroller with the integrated digital data processing Features : data filtering, clock recovery, data pattern recognition, integrated FIFO and TX data register. The automatic frequency control (AFC) feature allows the use of a low accuracy (low cost) crystal. To minimize the system cost, the Si4421 can provide a clock signal for the microcontroller, avoiding the need for two crystals. For low power applications, the Si4421 supports low duty cycle operation based on the internal wake-up timer. - - - - - - - - - - - - - - - - - - - - - - - - - - - - PIN ASSIGNMENT This document...