A VERY LOW POWER BANDPASS FILTER FOR LOW-IF APPLICATIONS

Abstract

This paper presents a second-order bandpass filter for IF frequencies in the range of 500 kHz–2 MHz. By using a single Gm–cell as a biquad filter, considerable saving in area and power is feasible. Higher order structures can be achieved by cascading this second-order block. This Gm-C filter achieves a dynamic range of 37 dB for 1% IM3 in Bluetooth while dissipating only 10.5 mW from 3.3 power supply in 0.35 μm CMOS process. The on-chip indirect automatic tuning circuit sets the filter center frequency to an external reference clock.