Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari

The Ion Sensitive Field Effect Transistor (ISFET) measure the pH-value and concentration of chemical activity by detecting ion hydrogen, H+ and this will change ISFET's threshold voltage, VTH. There is a need to extract the VTH changes using readout interfacing circuits (ROICs) instead of devic...

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Main Author:	Nazari, Siti Nor Nadiah
Format:	Thesis
Language:	English
Published:	2012
Subjects:	Electric apparatus and materials Electric circuits Electric networks
Online Access:	https://ir.uitm.edu.my/id/eprint/103075/1/103075.pdf
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id	my-uitm-ir.103075
record_format	uketd_dc
spelling	my-uitm-ir.1030752024-11-18T15:31:53Z Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari 2012 Nazari, Siti Nor Nadiah Electric apparatus and materials. Electric circuits. Electric networks The Ion Sensitive Field Effect Transistor (ISFET) measure the pH-value and concentration of chemical activity by detecting ion hydrogen, H+ and this will change ISFET's threshold voltage, VTH. There is a need to extract the VTH changes using readout interfacing circuits (ROICs) instead of device characterization. This project focuses on the design of ROICs to detect the output voltage, VOUT, whenever there is any change in VTH. Four different ROICs are designed; a constant-voltage constant-current biasing circuit, a direct feedback complementary ISFET/MOSFET pair, an indirect feedback complementary ISFET/MOSFET pair and a zener-based bridge-type ROIC by modifications of standard MOSFET's model VTH value using LTSPICE is made to reflect different sensor response under different chemical concentration. In this paper, ROICs are analyzed by investigating the features of operation mode, changes in VOUT versus VTH, changes in VOUT versus temperature, and the power consumption of each circuit. Result shows that the CVCC circuit has a very sensitivity circuitry since the VOUT changes is 0.9mV per pH unit and has a stability of mode of biasing operation, the indirect feedback CIMP has the highest performance due to the temperature rises, and the direct feedback CIMP has lowest power consumption. As a conclusion, the changing in VTH will change the VOUT with the CVCC circuit giving the most sensitive response. 2012 Thesis https://ir.uitm.edu.my/id/eprint/103075/ https://ir.uitm.edu.my/id/eprint/103075/1/103075.pdf text en public degree Universiti Teknologi MARA (UiTM) Faculty of Electrical Engineering
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
topic	Electric apparatus and materials Electric circuits Electric networks
spellingShingle	Electric apparatus and materials Electric circuits Electric networks Nazari, Siti Nor Nadiah Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
description	The Ion Sensitive Field Effect Transistor (ISFET) measure the pH-value and concentration of chemical activity by detecting ion hydrogen, H+ and this will change ISFET's threshold voltage, VTH. There is a need to extract the VTH changes using readout interfacing circuits (ROICs) instead of device characterization. This project focuses on the design of ROICs to detect the output voltage, VOUT, whenever there is any change in VTH. Four different ROICs are designed; a constant-voltage constant-current biasing circuit, a direct feedback complementary ISFET/MOSFET pair, an indirect feedback complementary ISFET/MOSFET pair and a zener-based bridge-type ROIC by modifications of standard MOSFET's model VTH value using LTSPICE is made to reflect different sensor response under different chemical concentration. In this paper, ROICs are analyzed by investigating the features of operation mode, changes in VOUT versus VTH, changes in VOUT versus temperature, and the power consumption of each circuit. Result shows that the CVCC circuit has a very sensitivity circuitry since the VOUT changes is 0.9mV per pH unit and has a stability of mode of biasing operation, the indirect feedback CIMP has the highest performance due to the temperature rises, and the direct feedback CIMP has lowest power consumption. As a conclusion, the changing in VTH will change the VOUT with the CVCC circuit giving the most sensitive response.
format	Thesis
qualification_level	Bachelor degree
author	Nazari, Siti Nor Nadiah
author_facet	Nazari, Siti Nor Nadiah
author_sort	Nazari, Siti Nor Nadiah
title	Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
title_short	Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
title_full	Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
title_fullStr	Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
title_full_unstemmed	Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari
title_sort	read-out interfacing circuit for isfet-based ph sensor vth monitoring / siti nor nadiah nazari
granting_institution	Universiti Teknologi MARA (UiTM)
granting_department	Faculty of Electrical Engineering
publishDate	2012
url	https://ir.uitm.edu.my/id/eprint/103075/1/103075.pdf
_version_	1818588077346521088

Read-out interfacing circuit for ISFET-based PH sensor VTH monitoring / Siti Nor Nadiah Nazari

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