A 262nW analog front end with a digitally-assisted low noise amplifier for batteryless EEG acquisition

This paper presents an analog front end (AFE) for a deploy-and-forget EEG monitoring system capable of indefinitely capturing and wirelessly transmitting a wide variety of neural measurements without battery power. This AFE design demonstrates a power consumption of 262nW per channel, lower than any other EEG acquisition system currently described in literature. In order to better utilize the smaller dynamic range of low power subthreshold ADCs, this architecture employs variable gain and a novel digital feedback loop to cancel electrode offset and other extraneous signals prior to amplification.