An Ultra Compact Integrated Front End for Wireless Neural Recording Microsystems

Abstract-The design and performance of an integrated front end for high-channel-count neural recording microsystems is presented. This front end consists of a 3-D micromachined microelectrode array, realized using a new architecture that allows simple and rapid microassembly. A 64-site 3-D multiprobe, realized using the new architecture, interfaces with tissue volumes of less than 0.01 mm³ and has a footprint of 1 mm². For amplification, filtering, and buffering of the recorded neural signals, a custom signal-conditioning circuit provides high gain (60 dB), low noise (4.8 μV_rms), and low power (50 μW) in an area of 0.098 mm². In addition, this circuitry implements bandwidth tuning, offset compensation, and wireless gain programmability. This new approach to system integration uses a microfabricated parylene overlay cable to electrically interconnect the 3-D array and signal-conditioning circuitry. In vivo results obtained using this integrated microsystem front end in its most compact form are presented.