A 192nW inverter-based chopper instrumentation amplifier for micropower ECG applications

This paper proposes a low-power inverter-based chopper instrumentation amplifier (IA) for ECG applications. A capacitively-coupled topology with chopper is employed while a two-stage inverter-based amplifier serves as the gain stage. Pseudo resistors are introduced to stabilize the output common-mode voltage of the amplifier and an improved switch-capacitor integrator with resistive attenuator is designed for the DC offset canceling (DCOC) loop. The instrumentation amplifier is implemented in a standard 0.18μm CMOS process. Simulation results show that the input referred noise is 1.28 μVrms ranging from 1Hz to 110Hz while consuming 192nW with a 1.2V supply.