Active-RC filters using two-stage OTAs with and without feed-forward compensation

Abstract

In this study, the design of active-RC filters using opamps with and without feed-forward-compensation is considered. Accurate analysis of the passive compensation scheme suggested in literature for lossless and lossy integrators using feed-forward-compensated opamps is carried out. The compensation for the lossy and lossless integrators using negative impedance converter for active filters using two cascaded gms in place of opamps is explored. Novel building blocks for realising the negative capacitance needed for exact compensation are proposed. To study the efficacy of the proposed compensation technique, a two-integrator loop biquad is considered. The PSPICE simulation results of Tow-Thomas biquad are presented to highlight the performance improvement obtained using the proposed compensation techniques.