VIS-SC-filters with reduced influences of parasitic capacitances

The large parasitic capacitances of MOS capacitors to substrate usually degrade the performance of VIS-SC-filters. In this paper, three design methods will be presented which reduce the effect of parasitics using filter structures consisting of cascaded earthed elements. The three design methods will be explained and analysed. Some experimental results will be given for a 5th-order lowpass filter with one transmission zero at a finite frequency, an integrated 3rd-order lowpass with cut off frequency of 170 kHz, and a 7th-order lowpass filter.