Digital assistable inverter-based band-pass filter

This paper proposes a low voltage inverter-based band-pass filter. The circuit is formed in class AB structure using only capacitors and CMOS inverters delivering wide signal swing and low voltage capabilities. With a digital assisting scheme, the center frequency around 900 MHz and 200 MHz bandwidth can be maintained with the power supply variation of 1.40-1.70 Volts. Simulation results of both biquadratic and 4/sup th/-order filters on 0.25 /spl mu/m CMOS processes confirm the functionalities and performances.