A Biopotential Recording IC with <10-ms-Settling Hybrid DC Servo Loop

This paper presents a low-noise, low-power biopotential recording IC with programmable gain and a reconfigurable number of channels. The analog front end (AFE) with tunable gain from 20 dB to 54 dB can select the number of channels and combination of channels for reconfigurable signal acquisition capability. The proposed hybrid DC-servo loop is employed for fast electrode DC offset (EDO) cancellation up to 240 mV within 10 ms. Designed in a 0.18-μm CMOS process, the proposed IC achieves input-referred noise (IRN) of 1.12 μVrms at the highest gain mode. The overall system achieves 66.35-dB SNDR with the successive approximation register (SAR) analogto-digital converter (ADC) and consumes 5.74 μW with 0.40 mm2 area per channel.