High input impedance insensitive second-order filters implemented from current conveyors

Two high input impedance second-order filters with active and passive sensitivities inferior or equal to the unit are described. Both of them use two second generation current conveyors, with positive current transfer (CCII⁺) and four passive components. The first circuit achieves a low-pass or high-pass transfer according to the kind of passive components used. The second circuit achieves a band-pass transfer. SPICE simulation results using translinear current conveyors are given and discussed. They confirm the validity of the analysis and they point out the high performances of these filters. Experimental results obtained with the AD844 AN transimpedance operational amplifier show the advantage of these implementations compared to conventional ones