Differential read-out architecture for CMOS ISFET microsystems |
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| Authors: | Chodavarapu V.P. Titus A.H. Cartwright A.N. |
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| Affiliation: | Dept. of Electr. Eng., State Univ. of New York, Buffalo, NY, USA; |
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| Abstract: | The operation of a pH (H/sup +/ 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 /spl mu/m commercial process. |
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