title: VLSI Potentiostat Array With Oversampling Gain Modulation for Wide-Range Neurotransmitter Sensing.
abstract: A 16-channel current-measuring very large-scale integration (VLSI) sensor array system for highly sensitive electrochemical detection of electroactive neurotransmiters like dopamine and nitric-oxide is presented. Each channel embeds a current integrating potentiostat within a switched-capacitor first-order single-bit delta-sigma modulator implementing an incremental analog-to-digital converter. The duty-cycle modulation of current feedback in the delta-sigma loop together with variable oversampling ratio provide a programmable digital range selection of the input current spanning over six orders of magnitude from picoamperes to microamperes. The array offers 100-fA input current sensitivity at 3.4-muW power consumption per channel. The operation of the 3 mm times3 mm chip fabricated in 0.5-mum CMOS technology is demonstrated with real-time multichannel acquisition of neurotransmitter concentration.
authors.forename: M
authors.initials: M
authors.lastname: Stanacevic
authors.forename: K
authors.initials: K
authors.lastname: Murari
authors.forename: A
authors.initials: A
authors.lastname: Rege
authors.forename: G
authors.initials: G
authors.lastname: Cauwenberghs
authors.forename: N V
authors.initials: NV
authors.lastname: Thakor