title: Wideband Fully-Programmable Dual-Mode CMOS Analogue Front-End for Electrical Impedance Spectroscopy.
abstract: This paper presents a multi-channel dual-mode CMOS analogue front-end (AFE) for electrochemical and bioimpedance analysis. Current-mode and voltage-mode readouts, integrated on the same chip, can provide an adaptable platform to correlate single-cell biosensor studies with large-scale tissue or organ analysis for real-time cancer detection, imaging and characterization. The chip, implemented in a 180-nm CMOS technology, combines two current-readout (CR) channels and four voltage-readout (VR) channels suitable for both bipolar and tetrapolar electrical impedance spectroscopy (EIS) analysis. Each VR channel occupies an area of 0.48 mm 2 , is capable of an operational bandwidth of 8 MHz and a linear gain in the range between -6 dB and 42 dB. The gain of the CR channel can be set to 10 kΩ, 50 kΩ or 100 kΩ and is capable of 80-dB dynamic range, with a very linear response for input currents between 10 nA and 100 μ A. Each CR channel occupies an area of 0.21 mm 2 . The chip consumes between 530 μ A and 690 μ A per channel and operates from a 1.8-V supply. The chip was used to measure the impedance of capacitive interdigitated electrodes in saline solution. Measurements show close matching with results obtained using a commercial impedance analyser. The chip will be part of a fully flexible and configurable fully-integrated dual-mode EIS system for impedance sensors and bioimpedance analysis.
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, WC1E 7JE London, UK. v.valente@ucl.ac.uk.
authors.forename: Virgilio
authors.initials: V
authors.lastname: Valente
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, WC1E 7JE London, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Demosthenous
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D017097:Electric Impedance; D006801:Humans; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*
keywords: analogue readout; electrical impedance spectroscopy (EIS); integrated circuits