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Voltage Biasing, Cyclic Voltammetry, & Electrical Impedance Spectroscopy for Neural Interfaces
Published on: February 24, 2012
A CMOS Self-Contained Quadrature Signal Generator for SoC Impedance Spectroscopy
Alejandro Márquez1, Jorge Pérez-Bailón2, Belén Calvo3
1Group of Electronic Design, Aragon Institute for Engineering Research (GDE-I3A), University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain. amarquez@unizar.es.
Abstract:
This paper presents a low-power fully integrated quadrature signal generator for system-on-chip (SoC) impedance spectroscopy applications. It has been designed in a 0.18 μm-1.8 V CMOS technology as a self-contained oscillator, without the need for an external reference clock. The frequency can be digitally tuned from 10 to 345 kHz with 12-bit accuracy and a relative mean error below 1.7%, thus supporting a wide range of impedance sensing applications. The proposal is experimentally validated in two impedance spectrometry examples, achieving good magnitude and phase recovery results compared to the results obtained using a commercial LCR-meter. Besides the wide frequency tuning range, the proposed programmable oscillator features a total power consumption lower than 0.77 mW and an active area of 0.129 mm², thus constituting a highly suitable choice as stimulation module for instrument-on-a-chip devices.
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