Operate the LM5009 so that the junction temperature does not exceed 125°C during normal operation. An internal thermal shutdown circuit is provided to protect the LM5009 in the event of a higher than normal junction temperature. When activated, typically at 165°C, the controller is forced into a low-power reset state, disabling the buck switch. This feature prevents catastrophic failures from accidental device overheating. When the junction temperature reduces below 140°C (typical hysteresis = 25°C), the buck switch is enabled and normal operation is resumed.