A 11G-Input-Impedance 700mV_pp-Input-Signal-Range 87dB-SNDR Direct-Digitization AFE for Wearable EEG Recording

This paper describes a wide dynamic range (DR) and high input-impedance direct-digitization analog front-end (AFE) for non-invasive EEG recording. The AFE utilizes a second-order 5-bit Delta-Delta Sigma ADC to shape low-frequency disturbances, such as DC electrode offset, power-line interference, and motion artifact while retaining high accuracy. Furthermore, the AFE adopts a pseudo-differential non-inverting amplifier and a C-DAC to achieve high input impedance in conjunction with high linearity. Fabricated in a standard 0.18 mu m CMOS process, the AFE achieves 11G Omega input impedance, 700mV(pp) input range, 95.3dB-DR and 87dB-SNDR while consuming 88.4 mu W from a 1.2V supply.