A 0.672 μW, 2 μVrms CMOS Current-Feeback ECG Pre-amplifier With 77 dB CMRR

This paper describes a differential CMOS bandpass amplifier dedicated for ECG acquisition. The proposed amplifier is constituted by a current-feedback instrumentation amplifier made from only 4 transistors in conjunction with capacitive-resistive feedback network. The amplifier circuit was designed using 0.35 micron CMOS and verified by post-layout simulation. It shows that the proposed amplifier provides 40 dB and 0 dB mid-band and dc amplifications, respectively. The amplifier bandwidth acquires 0.1 to 279 Hz. The input referred noise and input impedance of 2 μV
_rms
and 295 MΩ (at 50 Hz) are obtained. Monte-Carlo mismatch simulation confirms the amplifier's common-mode rejection ratio of 77 dB. Operated from a 2 V dc supply, the ECG amplifier consumes 672 nW.