Cascadable Three-Input Single-Output Current-Mode Universal Filter Using CDBAs

This paper presents the three-input single-output current-mode universal filter using three current differencing buffered amplifiers (CDBAs), two resistors, and two grounded capacitors. By properly selecting the input signals, the filter can realize five standard biquadratic functions, i.e. lowpass, bandpass, highpass, bandstop and allpass current responses from the same circuit topology. The natural frequency o and the bandwidth BW are independently controllable. No critical matching condition is required for realizing all the filter responses, and all the incremental parameter sensitivities are also low. The performances of the proposed circuit are confirmed by PSPICE simulations.