A High Gain, High CMRR, Low Noise Bio-Potential amplifier based on Switched Capacitor Feedback Amplifier

This paper describes a biopotential amplifier based on an operational transconductance amplifier (OTA) de-signed specifically for bio-potential recordings to achieve high gain and low noise. The amplifier uses a differential architec-ture with chopper modulators and pseudo-resistors to achieve a Common Mode Rejection Ratio (CMRR) of over 100 dB. The design has several key features, including precise and high steady gain, large output swing, good load-driving capabilities, high input impedance (Zin), and a small footprint. The paper compares the proposed circuit with other bio-potential ampli-fiers in the literature, focusing on key parameters such as gain, input referred noise (IRN), CMRR, and Zin. The outcomes show that the suggested amplifier has a gain of 57.7 dB, an IRN of 0.839 µVrms, a CMRR of 108.13 dB, and consumes 8.854 µW at 0.8 V. The proposed bio-potential amplifier was implemented using a 180 nm CMOS technology node and was verified through simulations using the Cadence Virtuoso Spec-tre Simulator. The findings indicate that the proposed design is highly effective for recording bio-potentials in various appli-cations.