Title :
An ISFET based sensing array with sensor offset compensation and pH sensitivity enhancement
Author :
Liu, Yan ; Toumazou, Chris
fDate :
May 30 2010-June 2 2010
Abstract :
In this paper, a novel chemical sensor system utilizing an Ion-Sensitive Field Effect Transistor (ISFET) for pH measurement is presented. Compared to other interface circuits, this system uses auto-zero amplifiers with a pingpong control scheme and array of Programmable-Gate Ion-Sensitive Field Effect Transistor (PG-ISFET). By feedback controlling the programable gates of ISFETs, the intrinsic sensor offset can be compensated for uniformly. Furthermore the chemical signal sensitivity can be enhanced due to the feedback system on the sensing node. A pingpong structure and operation protocol has been developed to realize the circuit, reducing the error and achieve continuous measurement. This system has been designed and fabricated in AMS 0.35μm, to compensate for a threshold voltage variation of ±5V and enhance the pH sensitivity to 100mV/pH.
Keywords :
chemical sensors; ion sensitive field effect transistors; pH measurement; ISFET based sensing array; auto zero amplifier; chemical sensor system; chemical signal sensitivity; feedback control; interface circuits; intrinsic sensor offset; pH measurement; pH sensitivity enhancement; pingpong control scheme; programmable gate ion sensitive field effect transistor; sensor offset compensation; voltage -5 V; voltage 5 V; Biomedical engineering; Biomedical measurements; Chemical sensors; Chemical technology; Control systems; FETs; MOSFET circuits; Passivation; Sensor arrays; Sensor systems;
Conference_Titel :
Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium on
Conference_Location :
Paris
Print_ISBN :
978-1-4244-5308-5
Electronic_ISBN :
978-1-4244-5309-2
DOI :
10.1109/ISCAS.2010.5536954
