Design and modeling of ISFET for pH sensing

This paper describes the modeling of a sensor suitable for biological applications using ISFET as the primary device. Since ISFET sensors are based on field effect principles, the standard equations of MOSFET have been extended to ISFET and integrated with the pH variation terms. The analysis of ISFET from electro-chemistry point has been presented and a low noise circuit of the complete sensor has been designed. Simulated results have been verified with the standard experimental ones.