A Wireless Neural-Interface SoC with Multimodal Chemical and Electrical Recording Capabilities

This article presents a wirelessly powered implantable System-on-Chip (SoC) for multimodal chemical and electrical neural signal monitoring. This is accomplished by: 1) proposing a low-power proportional-integral (PI) feedback loop that controls a background subtraction digital-to-analog converter (DAC) to track rapidly varying backgrounds and accelerate dynamic range (DR) extension; 2) employing an interpolating arbitrary waveform generator and reconfigurable potentiostat to provide low-ripple excitation across multiple modalities without off-chip components; 3) utilizing a rectifier-based dynamic voltage supply (DVS) that tracks electrode voltage requirements, significantly reducing high-voltage power loss. The platform supports fast-scan cyclic voltammetry (FSCV) with three-electrode sensors, local field potential (LFP) acquisition with organic electrochemical transistors (OECTs), and photoelectrochemical (PEC) sensors. Fabricated in a 65-nm complementary metal-oxide-semiconductor (CMOS) technology, the SoC occupies a core area of 0.33 mm² and a peak power consumption of 86 μW. Measurement results show DRs of 105.3 dB for FSCV and 138.8 dB for OECT. The detected dopamine increase in striatum verified the functionality of the neural interface SoC in vivo.