A New Fully Differential CMOS Capacitance to Digital Converter for Lab-on-Chip Applications

Author

Nabovati, Ghazal ; Ghafar-Zadeh, Ebrahim ; Mirzaei, Maryam ; Ayala-Charca, Giancarlo ; Awwad, Falah ; Sawan, Mohamad

Author_Institution

Dept. of Electr. Eng., Polytech., Montreal, QC, Canada

Volume

9

Issue

3

fYear

2015

fDate

Jun-15

Firstpage

353

Lastpage

361

Abstract

In this paper, we present a new differential CMOS capacitive sensor for Lab-on-Chip applications. The proposed integrated sensor features a DC-input ΣΔ capacitance to digital converter (CDC) and two reference and sensing microelectrodes integrated on the top most metal layer in 0.35 μm CMOS process. Herein, we describe a readout circuitry with a programmable clocking strategy using a Charge Based Capacitance Measurement technique. The simulation and experimental results demonstrate a high capacitive dynamic range of 100 fF-110 fF, the sensitivity of 350 mV/fF and the minimum detectable capacitance variation of as low as 10 aF. We also demonstrate and discuss the use of this device for environmental applications through various chemical solvents.

Keywords

CMOS integrated circuits; analogue-digital conversion; biological techniques; capacitance measurement; capacitive sensors; lab-on-a-chip; microelectrodes; DC-input capacitance; charge-based capacitance measurement; chemical solvents; differential CMOS capacitive sensor; digital converter; environmental applications; high capacitive dynamic range; integrated microelectrodes; integrated sensor features; lab-on-chip applications; metal layer; readout circuitry; CMOS integrated circuits; Capacitance; Capacitive sensors; Clocks; Electrodes; Modulation; $SigmaDelta$ modulator; CMOS; Capacitive sensor; chemical sensor; lab-on-chip;

fLanguage

English

Journal_Title

Biomedical Circuits and Systems, IEEE Transactions on

Publisher

ieee

ISSN

1932-4545

Type

jour

DOI

10.1109/TBCAS.2014.2336596

Filename

6876025