17.5 A 0.8mm3 Ultrasonic Implantable Wireless Neural Recording System With Linear AM Backscattering

Abstract

Miniaturization of implantable neural recording systems to micron-scale volumes will enable minimally invasive implantation and alleviate cortical scarring, gliosis, and resulting signal degradation. Ultrasound (US) power transmission has been demonstrated to have high efficiency and low tissue attenuation for mm-scale implants at depth in tissue [1, 2, 3], but has not been demonstrated with precision recording circuitry. We present an US implantable wireless neural recording system scaled to 0.8mm3, verified to safely operate at 5cm depth with state of the art neural recording performance an average circuit power dissipation of 13μW, and 28.8μW including power conversion efficiency. Sub-mm scale is achieved through single-link power and communication on a single piezocrystal (Lead Zirconate Titanate, PZT) utilizing linear analog backscattering, small die area, and eliminating all other off-chip components.