A planar IrO multichannel stimulating electrode for use in neural prostheses

Abstract

This paper describes a multisite stimulating probe capable of the precise delivery of sophisticated charge waveforms to neural structures on a chronic basis. The fabrication process for passive probes requires only four masks and is very high yield. Activated iridium oxide stimulating sites are shown to be compatible with the delivery of over 3 mC/cm2/phase in biphasic charge-balanced operation. In order to minimize the number of external probe leads, on-chip circuitry has been defined to allow per-channel current control at the 8-bit level using serial input data and a total of five external leads.