The MAX2450 combines a quadrature modulator and quadrature demodulator with a supporting oscillator and divide-by-8 prescaler on a monolithic IC. It operates from a single +3V supply and draws only 5.9mA. The demodulator accepts an amplified and filtered IF signal in the 35MHz to 80MHz range, and demodulates it into I and Q baseband signals with 51dB of voltage conversion gain. The IF input is terminated with a 400 thinfilm resistor for matching to an external IF filter. The baseband outputs are fully differential and have 1.2Vp-p signal swings. The modulator accepts differential I and Q baseband signals with amplitudes up to 1.35Vp-p and bandwidths to 15MHz, and produces a differential IF signal in the 35MHz to 80MHz range. Pulling the CMOS-compatible ENABLE pin low shuts down the MAX2450 and reduces the supply current to less than 1A. To minimize spurious feedback, the MAX2450's internal oscillator is set at twice the IF via external tuning components. The oscillator and associated phase shifters produce differential signals exhibiting low amplitude and phase imbalance, yielding modulator sideband rejection of 38dB. The MAX2450 comes in a QSOP package.