Fully Immersible Subcortical Neural Probes With Modular Architecture and a Delta-Sigma ADC Integrated Under Each Electrode for Parallel Readout of 144 Recording Sites

This paper presents a needle-shaped neural probe which integrates an incrementalΔ Σ-ADC under each electrode in an area of70× 70\,\,μ m². The modular architecture avoids global routing of noise sensitive neural signals and connects with a digital four-wire interface. The re-configurable 5.6/11.5 mm needle enables parallel readout of all 64/144 integrated recording sites and features a constant width and thickness of70× 50\,\,μ m²from top to bottom allowing to be fully implanted for deep brain monitoring applications. Platinum or iridium-oxide electrodes can be deposited in a custom post-CMOS process. The functionality of the recording system is demonstrated in anin vivosetup. The noise performance of 6.02μ Vᵣₘₛfor LFP signals (1–300 Hz) and 10.46μ Vᵣₘₛfor AP signals (300 Hz–10 kHz) is obtained at a power consumption of 39.14μ Wper recording site.