Comparison study of integrated potentiostats : Resistive-TIA, Capacitive-TIA, CT ΣΔ Modulator

Abstract

In this paper, a comparison between three different current readouts for micro-potentiostats is presented: resistive transimpedance amplifier (R-TIA), capacitive transimpedance amplifier (C-TIA), and current-mode continuous-time sigma-delta modulator (Current-CTSDM). The comparison is carried out on the signal transfer function, the required amplifier gainbandwidth (GBW), its input referred noise current, required area and power, and dynamic range. Each approach and its limitations are separately discussed. The three systems have been simulated using VerilogA models and the results are compared. It is shown that each system comes with its own limitations, however current-mode CTSDM are more beneficial due to their intrinsic digitization.