Third order Butterworth filter for current-mode operation employing equal valued capacitors, equal valued resistors and unity gain active elements

Abstract

This paper describes a current-mode third-order Butterworth filter realised with unity gain active elements and minimum number of passive components. All capacitors and resistors are equal valued. The core of the circuit realises HP, BP and LP functions easily. The filter exhibits high output impedance. Experimental results are included to verify theory.