Bandwidth enhancement of inverting amplifier using composite CFOA block

Abstract: In this paper, an active compensation method using two current feedback operational amplifiers (CFOAs) to enhance the bandwidth of finite gain inverting voltage amplifier for use as stand-alone amplifier is presented. It is also shown that the inexpensive passive compensation technique can be applied to composite CFOA based amplifier to improve the phase response in addition to bandwidth enhancement. The proposed circuits require one additional CFOA/ capacitor. The effect of finite output impedance at z terminal, input resistance at x terminal and current mirror pole of the CFOA is considered in the analysis. The proposed circuits have been simulated in PSPICE using a behavioral macro-model of the CFOA as well as that of a practical CFOA AD 844.

Keywords: Passive compensation; Current-feedback op-amp (CFOA); Active compensation