1.2 µW 41dB Ripple Attenuation Chopper Instrumentation Amplifier Using Auto-zero Offset Cancellation Loop

Abstract

This paper presents a low power low noise capacitively-coupled chopper instrumentation amplifier (CCIA) for the recording of neural signals, including electroencephalogram (EEG) and electrocardiogram (ECG). Due to the chopping technique, CCIA uses the proposed auto-zero offset cancelation loop to mitigate the output ripple. According to simulation results, the proposed CCIA obtains a ripple attenuation factor of 41.24 dB, the closed-loop gain is 40 dB with a bandwidth up to 800 Hz. A common-mode rejection ratio (CMRR) and a power rejection ratio are 108.9 and 87 dB, respectively, at 50 Hz. The proposed CCIA, which was implemented in a 0.18 µm CMOS technology, occupies only 0.09 squared millimeters. The total current consumption of CCIA is 1.2 µA from a 1 V supply.