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 mum CMOS process, includes 16 parallel amplifier channels, and measures 2.3 mm2 The amplifiers have a gain of 59.5 dB, a high cutoff frequency at 9.1 kHz and consume 75 microW 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 microm CMOS process. This version dissipates 142 microW and includes 64 to 8 site selection, 8 per-channel amplifiers each having a gain of 50.2 dB, a tunable low cutoff frequency, and a 7 kHz upper cutoff frequency. Real-time site impedance and circuit testing has been integrated in this design.