A CMOS continuous-time active biquad filter for gigahertz-band applications

A general high-Q biquad lter architecture capable of operating in the GHz range is proposed and analyzed. This lter, which is usable in bandpass and lowpass applications, utilizes two e ective Q-enhancement techniques to circumvent the low-Q characteristics inherent in the circuit. Simulation results employing standard 0.5 m CMOS technology have successfully veri ed that the center frequency tuning and hybrid Q-tuning techniques operate between 1GHz to 2.3GHz center frequencies with Q ranging from4.8 to over 1000. A tunable bandpass lter with a center frequency at 1.5GHz and a lowpass lter with a center frequency at 2.07GHz each having Q equal to 31 have been designed to have 63dB and 44dB input dynamic range, and power dissipation equal to 30.5mW and 27.8mW, respectively.