The design of CMOS gigahertz-band continuous-time active lowpass filters with Q-enhancement circuits

Abstract

A tunable second-order lowpass filter architecture capable of operating in the gigahertz frequency range is proposed. Two and-enhancement techniques are utilized to extend the Q tuning range. Simulation results employing standard 0.5 /spl mu/m CMOS technology have successfully verified that the center frequency tuning and the hybrid Q-tuning approach operate between 1.26 GHz and 2.3 GHz center frequencies with Q larger than 1000. A tunable lowpass filter with a center frequency at 2.07 GHz with a Q equal to 31 is designed to have 44 dB input dynamic range and 27.8 mW power dissipation.