An offset compensated CMOS current-feedback operational-amplifier

A new CMOS current-feedback operational-amplifier (CFOA) with a novel on-chip current-mode input offset voltage compensation circuit is presented. The offset voltage is reduced to less than 1 mV by varying the bias currents of the amplifier´s input buffer as a function of the mismatch between the NMOS and PMOS V_t´s (V_in and V _tp). The proposed compensation technique is suitable for both CMOS and BJT CFOA designs without degrading their high-frequency performance. As well, it is irrespective of process and temperature parameters because of its fully symmetrical architecture. Results of HSPICE simulation show that a GBW of around 100 MHz and a supply current of around 300 μA are achievable in a CMOS CFOA