Title :
A SAR based calibration scheme for ISFET sensing arrays
Author :
Yuanqi Hu ; Jiandong Li ; Georgiou, Pantelis
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll. London, London, UK
Abstract :
This paper presents an automatic calibration system for ISFET chemical sensing arrays to tune out any mismatch in sensitivity. Through exploitation of the high frequency spectrum of the sensed signal which does not contain any chemical reaction information, local sensitivity is examined and then calibrated through a successive approximation control mechanism and an 8-bit variable gain amplifier to provide high accuracy tuning. The total calibration process contains three phases, peak detection, AGC through a SAR and finally sensor readout of the detected chemical signal. Designed in a typical 0.35μm CMOS process, the system is capable of compensating a sensitivity deviation of up to 24% in an ISFET array, constraining the error to just 1.5%.
Keywords :
CMOS integrated circuits; MOSFET; amplifiers; calibration; chemical sensors; integrated circuit design; ion sensitive field effect transistors; readout electronics; sensor arrays; signal detection; AGC; CMOS process; ISFET chemical sensing array; SAR based calibration scheme; chemical reaction information; chemical signal detection; frequency spectrum; sensor readout circuit; size 0.35 mum; successive approximation control mechanism; successive approximation register; variable gain amplifier; word length 8 bit; CMOS integrated circuits; Calibration; Chemicals; Detectors; Electric potential; Gain control; Sensitivity;
Conference_Titel :
Circuits and Systems (ISCAS), 2014 IEEE International Symposium on
Conference_Location :
Melbourne VIC
Print_ISBN :
978-1-4799-3431-7
DOI :
10.1109/ISCAS.2014.6865223
