Two-Stage Differential Charge and Transresistance Amplifiers

A novel approach to the design of high-performance operational-amplifier-based differential charge and transresistance amplifiers is proposed. It is based on a two-stage topology: The first stage performs a differential measurement to single-ended signal conversion, providing a common-mode rejection that only depends on the matching between two resistors; the second stage filters the signal. Three novel topologies that are based on this technique are presented, analyzed, and measured, and design criteria are finally given. Their performance is compared with that of a state-of-the-art topology that is used as the benchmark, and it results in a better common-mode rejection ratio (CMRR).