A new method to improve the impedance of the CC-II's X input

Abstract

This paper presents a new method to improve the CC-II's X input impedance. The new method applies a double feedback scheme comprising both, series-shunt negative and series-series positive feedback paths. This method achieves input impedance levels below -15dBΩ (comparable to other reported methods), with controlled frequency peaking. Simulation results compare frequency performance of the proposed method with other reported methods, using the same reference CC-II. Effects of feedback on current and voltage transfers of the CC-II are also discussed, pointing to limitation factors on impedance reduction. ©2004 IEEE.