A versatile biopotential acquisition analog front end IC with effective DC offset and ripple rejection

This paper presents an analog front-end (AFE) IC for measuring biopotential signals such as electroencephalogram (EEG) and, electrocardiogram (ECG). The AFE employs the capacitively coupled chopper instrumentation amplifier architecture to achieve low noise. To reduce chopper ripple and respiration artifacts, a continuous-time AC-coupled ripple reduction loop (RRL) and DC servo loop (DSL) are employed. The proposed IC features differential gain of 72dB, and a common mode rejection ratio (CMRR) of 226 dB at 50 Hz, respectively. The input referred noise is simulated to be 1.6 μV rms in the bandwidth from 1 Hz to 100 Hz.