32-Channel Full Customized CMOS Biosensor Chip for Extracellular Neural Signal Recording

In this paper we present a full-customized CMOS biosensor integrated circuit (IC) design, layout, and implementation techniques for extracellular multichannel action potential recording applications. Schematics and simulation data for each of the sub-circuit macros are presented which includes contact sensors, unity gain buffer, variable gain amplifier and logic control unit. The chip provides a satisfactory signal-to-noise ratio for neural signals with amplitudes in the range of 50-500 muV and frequency spectrum in the range of 20-2000 Hz. The prototype IC was fabricated by MOSIS using AMI'S 1.5 mum, double poly, double level metal CMOS technology