A 15-Ch. 0.019 mm<SUP>2</SUP>/Ch. 0.43% Gain Mismatch Orthogonal Code Chopping Instrumentation Amplifier SoC for Bio-Signal Acquisition

Abstract

This paper proposes a 15-Ch. low power, small area, Orthogonal Code Chopping Instrumentation Amplifier (OCCIA). Orthogonal codes directly modulate each channel and merge into a single IA while performing dynamic offset compensation. Digitization-Before-Demodulation (DBD) transmits the combined data directly, which alleviates ripple noise, and completely removes the demodulation and TX encoding overhead from the SoC. The proposed OCCIA SoC in 0.18 mu m 1P6M CMOS achieves the lowest gain mismatch (0.43%) among recent multi-channel lAs with one of the smallest areas (0.019mm(2)/ch) while consuming 1.97 mu W/ch and low crosstalk (<-53.5dB) at 490Hz bandwidth