An Improved FVF Lowpass Filter with 0.02 fJ-FoM

A flipped voltage follower biquads with level shifting is presented. With balanced DC common mode between the input and output, the fourth-order lowpass filter for ECG signal with near 0-dB DC gain is established. This proposed ECG filter is simulated on a 0.35 μm CMOS technology with 0.8 V supply and 2.4 nW power consumption. With input-referred noise of 49.92 μVrms and -60 dB HD3 at the 35 mVp-100 Hz sinusoidal input signal, the dynamic range of 53.91 dB can be maintained. In comparison with recent nano-watt ECG filter, this work can be ranked as the best on Figure-of-Merit.