Three-input single-output current-mode universal filter using single CCCTA

The circuit topology for the realization of a low- component count current-mode universal biquadratic filter with three inputs and single outputs (TISO) is described. The described structure employs a single current-controlled conveyor transconductance amplifier (CCCTA), and only two grounded capacitors, without needing any external passive resisotrs. By properly selecting the relevant input signal, the circuit is capable of generating the five standard biquadratic filtering functions, i.e. lowpass, bandpass, highpass, bandstop and allpass current responses. The proposed filter can also be electronically tuned by external bias currents of the CCCTA. The circuit is analyzed for the non-idealities of the used CCCTA and possesses attractive low sensitivity performance. Simulation results are found to be in good agreement with the theoretical analysis.