The TMP43x can sense a fault at the DXP input that results from an incorrect diode connection or an open circuit. The detection circuitry consists of a voltage comparator that trips when the voltage at DXP exceeds (V+) – 0.6 V (typical). The comparator output is continuously checked during a conversion. If a fault is detected, the last valid measured temperature is used for the temperature measurement result, the OPEN bit (Status Register, bit 2) is set high, and, if the alert function is enabled, ALERT asserts low.
When not using the remote sensor with the TMP43x, the DXP and DXN inputs must be connected together to prevent meaningless fault warnings.