Voltage-mode universal biquad with five inputs and two outputs using two current feedback amplifiers

Abstract

A voltage-mode universal biquadratic filter using two current-feedback amplifiers (CFAs), two capacitors and four resistors, is presented. The new circuit has five inputs and two outputs and can realize all the standard filter functions, which are, lowpass, bandpass, highpass, notch and allpass filters, without changing the circuit topology. Some of the derived filter types enjoy the advantage of having two simultaneous output filter responses. One of the derived filter types enjoys the advantage of realizing non-inverting lowpass and inverting bandpass signals, simultaneously, with all the parasitic impedances of the CFAs can be absorbed by the outside passive components. Because the output impedance of the CFA is very low, the output terminals of the proposed configuration can be directly connected to the next stage.