A theoretical study of the stability of high frequency current feedback op-amp integrators

Abstract

In this paper, we present a comprehensive theoretical study of the stability of current feedback op-amps, when used with both resistive and capacitive feedback. The paper identifies some of the more subtle features of designing with current feedback op-amps, and the impact these features have on the amplifiers stability. There is a common misconception that the current feedback op-amp will oscillate when connected as a classical active R-C integrator; in this paper we prove that this is not necessarily the case and theoretically demonstrate that under certain design conditions the current feedback op-amp has in fact enormous potential for high frequency integrator design. Theoretical analysis is confirmed by both simulation and measured results using commercially available current feedback op-amps, and comparisons are made with classical voltage-mode op-amps.