A Low-Noise, High Input-Swing Instrument Amplifier

A low-noise, high input-swing instrument amplifier for biopotential monitoring based on 0.18 μm CMOS IC process is presented. This circuit is a current feedback amplifier, by improving the overall circuit structure, to achieve a very high electrode offset suppression. The circuit uses chopping technique to reduce flicker noise and uses DC offset cancellation loop to reduce amplifier offset. The proposed circuit consumes 56 μW from a 1.2 V supply, with in-band input-referred voltage noise density lower than 200 nV/√Hz, CMRR larger than 110 dB, ±300 mV electrode offset suppression and input impedance larger than 1 GΩ.