A 0.3-μW, 2.3-μVrms Bio-AFE With Auto-Calibrated Embedded DC-Servo-Loop.

This paper presents a bio-potential monitoring analog front end (AFE) with the capacitively-coupled chopper instrument amplifier. The aim is to reduce the high noise contribution of the conventional DC-servo loop (DSL) by proposing an embedded DSL to remove the charge-dividing effect. Additionally, a self-calibration scheme is proposed to reconfigure the main amplifier, which achieves digitally assisted elimination of the electrode DC offset (EDO), thereby boosting the cancellation range of EDO. The proposed AFE has been implemented in a 180-nm CMOS process, which has a power consumption of 0.32 μW at a 1.2-V supply. The input-referred noise of the AFE is 2.3 μVrms from 1 to 200 Hz with a noise efficiency factor of 4.4.