A robust ISFET pH-measuring front-end for chemical reaction monitoring
File(s)
Accepted version
Author(s)
Hu, Yuanqi
Georgiou, Pantelis
Type
Journal Article
Abstract
This paper presents a robust, low-power and compact ion-sensitive field-effect transistor (ISFET) sensing front-end for pH reaction monitoring using unmodified CMOS. Robustness is achieved by overcoming problems of DC offset due to trapped charge and transcoductance reduction due to capacitive division, which commonly exist with implementation of ISFETs in CMOS. Through direct feedback to the floating gate and a low-leakage switching scheme, all the unwanted factors are eliminated while the output is capable of tracking a pH reaction which occurs at the sensing surface. This is confirmed through measured results of multiple devices of different sensing areas, achieving a mean amplification of 1.28 over all fabricated devices and pH sensitivity of 42.1 mV/pH. The front-end is also capable of compensating for accumulated drift using the designed switching scheme by resetting the floating gate voltage. The circuit has been implemented in a commercially-available 0.35 μm CMOS technology achieving a combined chemical and electrical output RMS noise of 3.1 mV at a power consumption of 848.1 nW which is capable of detecting pH changes as small as 0.06 pH.
Date Issued
2014-05-01
Date Acceptance
2014-03-17
Citation
IEEE Transactions on Biomedical Circuits and Systems, 2014, 8 (2), pp.177-185
ISSN
1932-4545
Publisher
Institute of Electrical and Electronics Engineers
Start Page
177
End Page
185
Journal / Book Title
IEEE Transactions on Biomedical Circuits and Systems
Volume
8
Issue
2
Copyright Statement
© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000337154000004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Engineering, Biomedical
Engineering, Electrical & Electronic
Engineering
Chemical sensor
DNA
ion-sensitive field-effect transistor (ISFET)
pH sensor
reaction monitoring
sensor array
CMOS TECHNOLOGY
SENSOR
CIRCUIT
ARRAYS
CELL
Publication Status
Published
Date Publish Online
2014-05-01