Integrated switched-capacitor low-pass filter with combined anti-aliasing decimation filter for low frequencies

Abstract

A new combined antialiasing decimation filter is presented which allows the implementation of a low-frequency switched-capacitor filter on a single chip. Experimental results are presented for a CMOS second-order low-pass filter with 1 dB passband ripple, a cutoff frequency of 2 Hz, and a dynamic range of 84 dB. The decimation filter converts the input clock of 16 kHz into an output clock of 250 Hz. The integrated anti-aliasing filter has a low pole frequency of about 3 kHz.