Title :
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
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;
Journal_Title :
Biomedical Circuits and Systems, IEEE Transactions on
DOI :
10.1109/TBCAS.2014.2336596
