2048 Action Potential Recording Channels with 2.4 µVrms Noise and Stimulation Artifact Suppression

Here, we present 2048 low-noise, low-offset, and low-power action-potential recording channels, integrated in a multi-functional high-density microelectrode array. A resistively loaded open-loop topology has been adapted for the first-stage amplifier to achieve 2.4 µVrms noise levels at low power consumption. Two novel pseudo-resistor structures have been used to realize very low HPF corner frequencies with small variations across all channels. The adjustability of pseudo resistors has been exploited to realize a "soft" reset technique that suppresses stimulation artifacts so that the amplifiers can recover from saturation within 200 µs. The chips were fabricated in a 0.18 µm 6M1P CMOS process, and measurement results are presented to show the performance of the proposed circuit structures and techniques.