In summary, RTDs feature a wide temperature range (up to +850°C), excellent accuracy and repeatability, and reasonable linearity. Depending upon the application, RTDs are used in two, three, or four wire configurations. Signal conditioning is not particularly complicated except in the three wire case, for which matched current sources are required to minimize temperature measurement errors due to cable resistance. It is desirable for the interface circuit to detect short and open faults of the RTD, and a requirement to protect the ADC from overvoltages beyond its power supply rails. The MAX31865 from Analog Devices was introduced to monolithically solve this problem. It supports Pt100 and Pt1000 RTDs in two, three, or four wire configurations without the need for external current sinks. Its ADC resolution measures temperatures from -200°C to +800°C with automatic internal linearization. It continuously monitors the RTD cables for faults and disconnects the cable from the device if an overvoltage of up to ±50 V is detected.