A low-noise instrumentation amplifier with DC suppression for recording ENG signals

This paper presents an AC-coupled instrumentation amplifier for electroneurogram (ENG) activity recording. For this design, we evaluate gain and noise requirements based on interference sources (electrodes, power line, EMG). The circuit has been implemented in a commercially-available 0.35µm CMOS technology with total power consumption 460µW. The amplifier achieves CMRR 107 dB and integrated input referred noise 940 nV. The gain is 63 dB and the bandwidth is 0.5 Hz- 13 kHz. The chosen topology enables to minimise on-chip capacitance (only 27 pF), with a total chip area of 0.4mm2.