Current feedback neural amplifier with real time electrode offset suppression

This paper describes a direct coupled neural amplifier with active electrode offset suppression in order to avoid large coupling capacitors and complex chopper circuits. It describes a novel feedback scheme, where a low pass current mode feedback is applied to a regulated telescopic cascode amplifier, at the cascode nodes by using a modified transconductance block. This solution leads to fully differential input-differential output direct coupled neural amplifier, achieving a DC offset suppression range of ±200 mV, a chip area of 0.078 mm 2 per channel and an input referred noise of 2.5 μV rms over 1 Hz-5kHz bandwidth