The MAX31856 can use internal temperature sensor for cold junction compensation or apply values from an external temperature sensor. The maximum cold-junction temperature is clamped at 128°C and the minimum is clamped at -64°C. Optimal performance is achieved when the thermocouple cold junction and the cold junction sensor are at the same temperature. When a significant temperature differential between the internal sensor and the cold junction is unavoidable, an external temperature sensor may be used instead. The temperature measured by the external sensor may be written to the cold junction temperature register and used for cold-junction compensation.