INTRODUCTION There is a variety of temperature sensors on the market all of which meet specific application needs. The most common sensors that are used to solve these applica- tion problems include the thermocouple, Resistive Temperature Detector (RTD) thermistor, and sili- con-based sensors. For an overview and comparison of these sensors, refer to Microchip’s AN679, “Temper- ature Sensing Technologies”. This application note focuses on circuit solutions that use Negative Temperature Coefficient (NTC) ther- mistors in the design. The Thermistor has a non-linear resistance change-over temperature. The degree of this non-linearity will be discussed in the “Hardware Linearization Solutions” section of this application note. From this discussion, various linearization resistor net- works will be shown with error analysis included. Finally, the signal conditioning path for the thermistor system will be covered with complete application cir- cuits from sensor or microprocessor. AN685 Thermistors in Single Supply Temperature Sensing Circuits generated by the power dissipated by the element. Any Author: Bonnie C. Baker change in the flow of the liquid or gas across the device Microchip Technology Inc. changes the power dissipation factor of the thermistor element. In this manner, the resistance of the ther- INTRODUCTION mistor is changed, relat……