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

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 mm ² . To enhance the dynamic range, we utilize a 3 ^rd -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.