The RTD Reference Design demonstrates how to instrument Resistive Temperature Detector (RTD) and accurately measure temperature. This solution uses the MCP3551 22-Bit ADC to measure voltage across the RTD. The ADC and the RTD are referenced using an onboard reference voltage and the ADC inputs are directly connected to the RTD terminals. This provides a ratio metric temperature measurement. The solution uses a current limiting resistor to bias the RTD. It provides a reliable and accurate RTD instrumentation without the need for extensive circuit compensation and calibration routines. In addition, this reference design includes a silicon temperature sensor, MCP9804. This sensor is used for comparison only, it is not needed to instrument an RTD. The MCP3551 and MCP9804 outputs are read using a USB PIC® MCU. This controller is also connected to a PC using a USB interface. The Thermal Management software is used to plot the RTD temperature data in strip chart format.