A High DR High-Input-Impedance Programmable-Gain ECG Acquisition Interface with Non-inverting Continuous Time Sigma-Delta Modulator

Abstract

This paper presents a power-efficient, high dynamic range, high input impedance data acquisition circuit for an implantable electrocardiogram (ECG) detector in 65 nm CMOS, occupying an active area of 0.225 mm2. To enhance the dynamic range, we utilize a 3rd-order continuous-time sigma-delta modulator with a programmable input gain coefficient and an embedded antialiasing filter. The implementation of the non-inverting integrator allows a high input impedance for the ECG application. The measurement results show that it obtains 84.2dB SNDR in a 150Hz bandwidth with a 1V power supply, consuming 5.4μW at a nominal gain of 0dB. The maximum dynamic range is 99.3dB with the programmable gain activated from 0 to 18dB.