The TMP119 supports the SMBus alert function. When the ALERT pin is connected to an SMBus alert signal and a controller senses that an alert condition is present, the controller can send out an SMBus ALERT command (0001 1001) to the bus. If the ALERT pin is active, the device acknowledges the SMBus ALERT command and responds by returning the target address on the SDA line. The eighth bit (LSB) of the target address byte indicates if the alert condition is caused by the temperature exceeding T_(HIGH) or falling below T_(LOW). The LSB is high if the temperature is greater than T_(HIGH), or low if the temperature is less than T_(LOW). See Figure 7-12 for details of this sequence.

In the event that the device with the lowest I²C address in continuous conversion mode sees an alert, the controller can temporarily disable Alert mode in this device until all alerts in the system are cleared to prevent this device from blocking other devices with higher I²C addresses from reporting to the controller.

If multiple devices on the bus respond to the SMBus ALERT command, arbitration during the target address portion of the SMBus ALERT command determines which device clears the alert status of that device. The device with the lowest two-wire address wins the arbitration. If the TMP119 wins the arbitration, the TMP119 ALERT pin becomes inactive at the completion of the SMBus ALERT command. If the TMP119 loses the arbitration, the TMP119 ALERT pin remains active.