CMOS Integrated VDBA-ISFET Device for Water Quality Monitoring

This study presents a performance analysis of low power CMOS Integrated “Current Conveyor Ion Sensitive Field Effect transistor” (CC-ISFET). The study’s main focus is on simulation of power and performance analysis of ISFET device, which is used for water quality monitoring. This approach can improve calibration of device to a fairly wide range without the use of a high speed digital processor. The conventional devices generally used, consume high power and are not stable with temperature and frequency variations for long term monitoring. The conventional device [1] has a drawback of low value of slew rate, high power consumption, and non linear characteristics but in this novel design, the device exhibits a better slew rate, piecewise linear characteristics, and seen consuming low power of the order of 5.7µW. The functionality of the circuit is tested using Tanner simulator version 15 for a 70nm CMOS process model. Very high speed integrated circuit Hardware description language (VHDL) code for the same scheme is simulated on Xilinx ISE 10.1 and various simulation results are obtained. The proposed circuit reduces total power consumption per cycle, increases speed of operation, fairly linear and is simple to implement.This device has a simple architecture, and hence is very suitable for water quality monitoring applications.