When the LM3645 die temperature reaches 150°C, the thermal shutdown detection circuit trips, forcing the LM3645 into standby and writing a '1' to the corresponding bit of the Thermal Fault Report Register (bit [0] in reg 0x16). The LM3645 is only allowed to restart after the Thermal Fault Report Register (0x17) is read, clearing the fault flag. Upon restart, if the die temperature is still above 150°C, the LM3645 resets the Fault flag and re-enters standby.