Integrated Implantable Electrode Array and Amplifier Design for Single-chip Wireless Neural Recordings

A four-channel micro-electrode array (MEA) and a low noise amplifier are integrated in a standard CMOS process as part of a single-chip wireless neural recording and stimulation system. The design is tested for acquiring action potential and local field potential of live neurons. The neural amplifier uses capacitive feedback structure to avoid dc baseline drifting. Fabricated using GlobalFoundries' 45RFSOI CMOS technology and post-processed to form the integrated MEA, measured neural probe output impedance is between $3.5\ \mathrm{k}\Omega$ to $250\ \mathrm{k}\Omega$ across 20 Hz to 102 kHz with phase shift between −70° to −10°. The amplifier can achieve 35 dB voltage gain across 1 Hz to 10 kHz, and its input referred noise is $4.9\ \mu \mathrm{Vrms}$ over 10 Hz to 10 kHz bandwidth.