Electrically tunable CMOS biquad cells implementation of high-order filters [articol]

Abstract

This paper presents a new design approach which generates high-order electrically tunable HF ICcompatible filters. The realized circuits are composed only from CMOS linear transconductance elements and grounded capacitors. We propose a new CMOS universal multiple inputs biquad filter cell, which permits independent electric controls of filter parameters. Several of these biquad cells are incorporated in a low-sensitivity coupled-biquad structure in order to realize an active HF filter. This structure implements a node-voltage simulation of an equivalent LC ladder passive filter. A fifth-order lowpass filter is simulated with the end to demonstrate the performances of CMOS linear transconductors in the achievement of HF high-orders filters.