Design of 1.55 NEF, 2μA, Chopper Based Amplifier in 40nm CMOS for Biomedical Multichannel Integrated System

P. Wargacki, P. Kmon (AGH Univ. of Science and Techn., Poland)

Below paper presents a design of a low-noise chop- per based amplifier for biomedical recordings. It is a part of a multi-channel integrated system fabricated in 40nm CMOS technology. It features a DC stabilizing loop for compensating electrode offset and positive feedback for input impedance boost- ing. The first stage uses double current reuse. Design consumes 2μA per channel under 1V supply voltage and occupies only 0.044mm2of silicon area. A novel input stage presented in this work combines a low noise performance of a stacked input pair with the high DC gain of the folded cascode amplifier. The simulated input-referred noise is 0.96μV rms in the 0.5–100Hz frequency band and 2.8μV rms in the 100Hz–10kHz frequency band, respectively, leading to a noise-efficiency factor of 5.29 (0.5–100Hz) and 1.55 (0.1–10kHz).