A tunable low power BiCMOS continuous-time G/sub m/-C lowpass filter

A monolithically integrated 5/sup th/ order lowpass filter with a tunable cutoff frequency is presented. The cutoff frequency can be tuned via a control voltage between 30 kHz and 180 kHz. This circuit may serve as channel selecting filters in direct conversion receivers for various cellular radio services with different bandwidth (e.g. IS-54, GSM, etc.). The main design goals are low power consumption, a large tuning range, good linearity and a high dynamic range.