6.5μW 92.3DB-DR Biopotential-Recording Front-End with 360MVpp Linear Input Range

Abstract

This paper presents a direct-digital-conversion biopotentialrecording front-end with 92.3dB dynamic range at an input range of 360m V pp . The proposed front-end is a capacitively -coupled 3rd-order Gm-C CT ΔΣM with a 5-bit SAR quantizer. The capacitively-coupled summing circuit increases linearity of the ΔΣM, and a 3rd-order Gm-C loop filter and a 5-bit SAR ADC reduces quantization noise level. The proposed front-end is fabricated in 0.18μm CMOS, and achieves 91.3dB SNDR and 1.8μ V rmsinput-referred noise over 100Hz BW. Also, an invitro LFP recording is performed to verify the front-end.