A low noise front-end for multiplexed ENG recording using CMOS technology

Multi-electrode cuffs (MECs) have been proposed as a means for the parallel recording of naturally-occurring neural signals. Compared to a conventional tripole cuff providing a single channel signal, additional information about the velocity and direction of nerve signals can be extracted from the multi-electrode recordings. Moreover, interference suppression is improved as the presented analysis shows. In this paper a new recording system is proposed, each channel of which consists of a low-noise input buffer employing lateral bipolar transistors to provide an impedance match to the tissue and a path to ground for the switching currents of a single high-gain amplifier, which is multiplexed between channels. The proposed system provides low-noise, low-power operation and practically identical channel gains and is suitable for integration in a CMOS process.