A configurable 5.9 μW analog front-end for biosignal acquisition

Abstract

This paper presents a configurable analog front-end (AFE) for the recordings of a variety of biopotential signals, including electromyography (EMG), electrocardiogram (ECG), electroencephalogram (EEG), action potential (AP) signals, etc. The first stage of the AFE employs a chopper-stabilized current-reuse complementary input (CRCI) telescopic-cascode amplifier to achieve high noise-power efficiency and suppress 1/f noise. A tunable impedance-boosting loop (IBL) is utilized, which is robust to process variation and parasitic capacitance and increases the input impedance from 4.3 MΩ to 102 MΩ. The proposed AFE is fabricated in a 0.13 μm CMOS process. The AFE has a mid-band gain from 45.2-71 dB. The low-pass corner is tunable in the range of 70-400 Hz and 1.2-7 kHz. When configured for EEG recordings (0.7-100 Hz), the AFE draws 5.4 μW from a 1.2 V supply while exhibiting input-referred noise of 0.45 μVrms, corresponding to a noise efficiency factor (NEF) of 3.7. When configured for AP recordings (0.7 Hz-7 kHz), the AFE consumes 5.9 μW with input referred noise of 2.93 μVrms and a NEF of 3.0.