The HFA3683A is a monolithic SiGe half duplex RF/IF transceiver designed to operate in the 2.4GHz ISM band.The receive chain features a low noise,gain selectable amplifier (LNA) followed by a down-converter mixer. An up-converter mixer and a high performance preamplifier compose the transmit chain.The remaining circuitry comprises a high frequency Phase Locked Loop (PLL) synthesizer with a three wire programmable interface for local oscillator applications.