Current Feedback op-Amp Utilizes New Current Cell to Enhance the CMRR

Despite excellent high frequency and high speed performance, current-feedback operational ampli ̄ers (CFOAs) generally exhibit poor common-mode rejection (CMRR) properties, which limit their utility [Analogue IC design: The current mode approach, IEE Circuits and Systems Series, Peter peregrinus, 1990]. A novel current feedback operational ampli ̄er (CFOA) with improved performance is presented. The proposed CFOA has a new current-cell [Novel currentfeedback operational ampli ̄er Design Based on a °oating circuit technique, IEE Colloquium on Analogue Signal Processing, 1998], to bias the entire circuit, which achieves an incremental output resistance twice that of the well-known \Wilson" circuit. Simulation results of this new CFOA architecture indicate that the ampli ̄er exhibits performance characteristics superior to those obtained with an established input architecture: in particular, the CMRR (common-mode rejection ratio) is 91 dB, and the d.c. o®set voltage less than 26 V.