Cascadable multiple-input single-output current-mode universal filter based on current differencing buffered amplifiers

A multiple-input single-output current-mode universal filter based on current differencing buffered amplifiers (CDBAs) is presented in this paper. The proposed configuration consists of three CDBAs, two virtually grounded 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 circuit has a low-input impedance and high-output impedance, which can enable cascading in current-mode operation without additional buffers. The natural frequenc ωoy and the parameter ωo/Q 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.