Analysis and design of 3-D potentiostat for deep brain implantable devices

We present the analysis and design of a 3-D potentiostat, an important part of the next generation of the deep brain implantable devices. The potentiostat with interfacing electrochemical sensor comprises a system for measurement of the concentration of the neurotransmitter molecules. We first introduce the architecture of a 2-D potentiostat implemented as the first-order incremental current-sensing sigma–delta converter. The fabricated design demonstrates a 100 fA sensitivity with dynamic range spanning through six orders of magnitude. The same architecture is transferred into 3-D technology with separate tiers for the analog and digital circuitry. The analysis of the 3-D design reveals that the sensitivity is limited by the TSV-related noise coupling.