A contribution to the 2nd-order LP filters design

Abstract

This paper discusses some aspects of design and realization of the simple second-order low-pass building blocks (LP-SFB), suitable for less demanding anti-aliasing and reconstruction filters. The main attention is devoted to the ”single active device” solutions, based on CC-II type current conveyor or transconductance amplifier (OTA). As the template, the Rauch's multiple-feedback circuit was used. Presented SFBs show very low ω0 and Q sensitivities and, in contrast to the known Sallen-Key circuits, save good stop-band attenuation. Proposed design uses DE algorithm and allows almost independent tunning of ω0 and Q parameters.