The design of new low-voltage CMOS VHF continuous-time lowpass biqaud filters

A low-voltage very high-frequency CMOS lowpass biquad filter using simple transconductance (Gm) amplifier and transresistance (Rm) amplifiers is proposed and analyzed. Both single-ended and fully-differential topologies have been developed in this paper. Simulation results show that for the single-ended lowpass biquad filter, the center frequency fo can be tuned from 123 MHz to 181.9 MHz whereas the power dissipation varies from 2.92 mW to 3.36 mW. For 1% THD, the equivalent maximum output signal of the single-ended filter with center frequency 181.9 MHz is about 67 mV with a 2.5 V power supply. For the fully-differential lowpass biquad filter, the center frequency fo can be tuned from 124 MHz to 218.7 MHz whereas the power dissipation varies from 7.94 mW to 9.44 mW. For l% THD, the equivalent maximum output swing of the fully-differential filter with center frequency 218.7 MHz is about 414 mV under fully-balanced inputs with a 2.5 V power supply