Thermistor Temperature Sensing with MCP6SX2 PGAs

This application note shows two circuits that use a precise, negative temperature coefficient (NTC) thermistor for temperature measurement. The thermistor is placed in a resistive divider to linearize the voltage response to temperature. This voltage is then processed in the analog domain, by the MCP6S2X Programmable Gain Amplifier (PGA), before converting to digital. The first circuit uses a more precise Analog-to-Digital Converter (ADC), while the second circuit employs a less precise ADC. The design tradeoffs between these approaches is discussed.