A Very Low Power 10 MHz CMOS Continuous-Time Bandpass Filter With On-Chip Automatic Tuning

A second-order CMOS continuous-time bandpass filter with a tuneable 4-12 MHz center frequency (fc) is presented. The design has been done by using a new second-order block which is based on Gm-C method. This Gm-C filter achieves a dynamic range of 30 dB for 1% IM3, and Q equal to 58 at 12 MHz, while dissipating only 10.5 mW from 3.3 V power supply in 0.35 μm CMOS process. The on-chip indirect automatic tuning circuit uses a phase locked loop which sets filter center frequency to an external reference clock.

Keywords:

bandpass filter , Gm-C , quality factor , dynamic range , IM3 , automatic tuning , PLL