Title :
Differential read-out architecture for CMOS ISFET microsystems
Author :
Chodavarapu, V.P. ; Titus, A.H. ; Cartwright, A.N.
Author_Institution :
Dept. of Electr. Eng., State Univ. of New York, Buffalo, NY, USA
fDate :
6/9/2005 12:00:00 AM
Abstract :
The operation of a pH (H+ ion concentration) sensitive ion-sensitive field-effect transistor (ISFET) microsystem with a sensitivity of 40-45 mV/pH is demonstrated. This system has two identical ISFETs as the inputs to a pair of ISFET operational transconductance amplifiers (IOTAs) arranged in a novel differential architecture. The IOTAs have different sized p-MOSFET load transistors that enable pH sensitive operation without any post-fabrication processing or material deposition. The CMOS ISFET chip is fabricated in an unmodified 1.5 μm commercial process.
Keywords :
CMOS integrated circuits; ion sensitive field effect transistors; operational amplifiers; pH measurement; readout electronics; 1.5 micron; CMOS ISFET microsystems; ISFET operational transconductance amplifiers; differential architecture; differential read-out architecture; load transistors; material deposition; p-MOSFET; pH sensitive ion-sensitive field-effect transistor; post-fabrication processing;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20051044
