JEDEC specification JESD22-A108C, section 4.2.1 [1] addresses HTRB testing of power devices and defines the acceptable test condition as one where the ambient temperature keeps the junction temperatures of the DUTs at or above 125 °C. A108C also declares that the TJ of the DUTs should not exceed the TJMAX specified in the manufacturer’s data sheet (typically 150 °C, for Silicon devices).