The TCAN1144-Q1 and TCAN1146-Q1 has two trigger points for thermal events. The first is a thermal shutdown warning. Once the temperature exceeds this limit, an interrupt is issued. The second is the actual thermal shutdown (TSD) event.

This is a device preservation event. If the junction temperature of the device exceeds the thermal shut down threshold the device turns off the CAN transceiver and CAN transceiver circuitry thus blocking the signal to bus transmission path. A thermal shut down interrupt flag is set, and an interrupt is inserted so that the microprocessor is informed. If this event happens, other interrupt flags may be set as well. An example is a bus fault where the CAN bus is shorted to Vbat. When this happens, the digital core and SPI interface is still active. After a time of ≈ 300 ms the device checks the temperature of the junction. Thermal shutdown timer, t_TSD, starts when TSD fault event starts and exit to sleep mode when TSD fault is not present when TSD timer is expired. While in thermal shut down protected mode, a SPI write to change the device to either Normal or Standby mode is ignored while writes to change to sleep mode are accepted.

If the TSD event takes place and fail-safe mode is enabled, the same process takes place with and instead off thermal shut down protected stated the device enters fail-safe mode.