Realization of current-mode third order Butterworth filters employing equal valued passive elements and unity gain buffers

摘要

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