Neural recording front-end designs for fully implantable neuroscience applications and neural prosthetic microsystems

An implantable neural recording front-end has been designed in two versions. The first is a multi-channel signal-conditioning ASIC for use with any neural recording probe technology. This ASIC was implemented in a commercial 0.5 mu m CMOS process, includes 16 parallel amplifier channels, and measures 2.3mm(2). The amplifiers have a gain of 59.5dB, a high cutoff frequency at 9.1kHz and consume 75 mu W per channel. The low cutoff frequency is independently tunable on each channel to accept or reject field potentials. This chip is small enough to be chronically packaged for experiments in awake behaving. animals or it can be integrated into a fully implantable neural recording microsystem. The second version of the front-end is a neural recording probe with integrated signal conditioning circuitry on the back-end implemented in a 3 mu m CMOS process. This version dissipates 142 mu W and includes 64 to 8 site selection, 8 per-channel amplifiers each having a gain of 50.2dB, a tunable low cutoff frequency, and a 7kHz upper cutoff frequency. Real-time site impedance and circuit testing has been integrated in this design.