A band-tunable, multichannel amplifier for neural recording with AP/LFP separation and dual-threshold adaptive AP detector

This article presents a low-power low-noise neural recording system comprising a set of 4-channel amplifiers and a dual-threshold adaptive action potential detector. The front-end amplifier is optimized for power efficiency, noise, and silicon area. A balanced tunable pseudo-resistor is used to acquire local field potential (LFP) and action potential (AP) separately. The post-layout simulation results show that the system achieved input referred noise 4.7μVrms and noise efficiency factor (NEF) 2.79 with mid-band gain of 51.9dB and power consumption of 5.22μW. The bandwidth is highly tunable in the range of 2.38Hz-300Hz for high-pass corner and 248Hz-12.9kHz for low-pass corner, which can acquire AP and LPF without out-band noise. The proposed dual-threshold adaptive AP detector can capture action potential precisely from background activity, thus data reduction can be realized by only processing these significant waveforms. The results show that the proposed low-power, low-noise biomedical system is suitable for implantable device applications.