An implantable multielectrode array with on-chip signal processing

This active probe can be used for the long-term recording of extracellular neural biopotentials and as a basis for closed-loop neural prostheses. The probe incorporates on-chip circuitry for amplifying, multiplexing, and buffering neural signals recorded from ten recording electrodes spaced 100-μm apart. It requires only three leads and operates from a single 5-V supply. On-chip self-test circuitry for testing electrode impedance levels is provided. The on-chip circuitry is fabricated in a die area of 1.3 mm/SUP 2/ using 6-μm LOCOS enhancement-depletion NMOS technology, and dissipates 5 mW of power. The probe is 4.7 mm long and 15 μm thick, and has a shank which tapers from 160 μm near the base to less than 15 μm near the tip.