Gm-C Filter with Automatic Calibration Scheme

Abstract

This work presents a fifth-order OTA-C band-pass filter applying Elliptic low-pass filter and complex filter techniques. The frequency error of the filter due to the effect of process variations is induced by integrating the passive components with the operational transconductance amplifier on chip. A filter circuit with automatic calibration scheme can make the frequency less dependent on process, voltage, and temperature variations. The layout of a test chip is realized using a 0.18 um 1P6M CMOS process. Post-layout simulation demonstrates that the center frequency of the band pass filter is 450 kHz and the dynamic range is 35 dB, It has a total power consumption of 0.14mW.