A Low-Power Integrated Neural Interface with Digital Spike Detection and Isolation

We present the design of an integrated neural interface intended for multi-channel neural recording. The design features a mixed-signal part that handles neural signal conditioning, digitization, and time-division multiplexing, and a digital part that provides control, threshold detection, isolation of spikes, and serial communications towards a host interface. The detection and isolation strategy preserve the entire neuronal spikes waveshapes by means of synchronized internal data buffering. This bandwidth reduction scheme prompts for better postprocessing results and improved performance in prosthetics applications. Both parts of the presented neural interface were fabricated separately in a CMOS 0.18- mum process. The whole neural interface features 16 channels for validation; besides, the proposed approach is scalable to larger channel counts. In fact, it is suitable for implementation of implantable microsystems including several hundreds of recording channels. The performance of the implemented multi-channel interface was validated in vitro with real neural waveforms.