CFOA BASED MIXED MODE BIQUAD ACTIVE FILTERS CONFIGURATIONS

Abstract

A current feedback operational amplifier (CFOA) based mixed-mode active biquad filter configuration is illustrated in this work. The proposed topology provides second-order low-pass(LP), band-pass(BP), high-pass (HP) and band reject (BR) responses simultaneously at different output nodes. The topology’s major feature is its ability to operate in voltage mode(VM), current mode(CM), transadmittance mode(TAM) and transimpedance mode(TIM) without requiring any circuit reconfiguration. The circuit is realized using CFOA-based summer followed by two CFOA-based integrators and CFOA based voltage to current converter, making the circuit suitable for integrated implementation. Different mixed mode transfer functions are derived using ideal CFOA characteristics. Theoretical analyses are validated through simulation results, performed in Pspice, confirming correct second order frequency responses using AD844 type IC CFOA.