An Area- and Energy-Efficient 16-Channel, AC-Coupled Neural Recording Analog Frontend for High-Density Multichannel Neural Recordings

We present an AC-coupled modular 16-channel analog frontend with 1.774 fJ/c-s.mm(2) energy- and area-product for a multichannel recording of broadband neural signals including local field potentials (LFPs) and extracellular action potentials (EAPs). To achieve such a small area-and energy-product, we employed an operational transconductance amplifier (OTA) with local positive feedback, instead of a widely-used folded cascode OTA (FC-OTA) or current mirror OTA for conventional neural recordings, while optimizing the design parameters affecting performance, power, and area trade-offs. In addition, a second pole was strategically introduced in the LNA to reduce the noise bandwidth without an in-channel low-pass filter. Compared to conventional works, the presented method shows better performance in terms of noise, power, and area usages. The performance of the fabricated 16-channel analog frontend is fully characterized in a benchtop and an in vitro setup. The 16-channel frontend embraces LFPs and EAPs with 4.27 mu V rms input referred noise (0.5-10 kHz) and 53.17 dB dynamic range, consuming 3.44 mu W and 0.012 mm(2) per channel. The channel figure of merit (FoM) of the prototype is 147.87 fJ/c-s and the energy-area FoM (E-A FoM) is 1.774 fJ/c-s.mm(2).

Automated summary

A novel AC-coupled modular 16-channel analog frontend has been introduced for multichannel recording of broadband neural signals with improved performance and efficiency through the use of a new OTA design and optimized parameters.