A Novel Pseudo-PMOS Integrated ISFET Device for Water Quality Monitoring

The paper presents a performance analysis of novel CMOS Integrated pseudo-PMOS ISFET (PP-ISFET) having zero static power dissipation. The main focus is on simulation of power and performance analysis along with the comparison with existing devices, which is used for water quality monitoring. The conventional devices, generally used, consume high power and are not stable for long term monitoring. The conventional device has the drawbacks of low value of slew rate, high power consumption, and nonlinear characteristics, but in this novel design, due to zero static power, less load capacitance on input signals, faster switching, fewer transistors, and higher circuit density, the device exhibits a better slew rate and piecewise linear characteristics and is seen consuming low power of the order of 30？mW. The proposed circuit reduces total power consumption per cycle, increases the speed of operation, is fairly linear, and is simple to implement. 1. Introduction Water is vital for all known forms of life. With the expansion of industrial production and increase in the population every year, wastewater produced by industry is discharged into rivers and lakes due to which the quality of water is degraded. Hence, it is the most urgent to take an effective measure to monitor and protect the water resources. The supervision of water quality is generally done by taking and analysing some liquid samples in the laboratory. This method is very expensive and tedious, and it can take several weeks to get tests result. Many research works have contributed to design quality measuring devices [1]. But it is always a challenge to select a more precise and accurate device for monitoring the quality. In today’s scenario, as most of the complex functions are realized, due to which there is a growing demand for high density VLSI circuits resulting in scaling and an exponential increase of leakage or static power in deep submicron technology becomes essential to be taken care off. Therefore, reducing static power consumption of portable devices for water quality monitoring applications is highly desirable for a long term monitoring. As the size of the transistor decreases (i.e., technology), the transistors density per unit chip Increases. The scaling of the device and very large integration of the transistors will lead to an increase in temperature and higher power consumption [2]. This increase in temperature will lead the increase in the overall cooling cost and complicated packaging techniques. The total power consumption in high performance digital circuits is mainly due to