Automotive temperature grade
The 1.5SMCJ60CA-AQ: Junction temperature range is -50°C to 150°C — this is the automotive ambient band. A chassis-mounted TVS in an engine-compartment enclosure that sees 125 °C ambient still has 25 °C of junction headroom before the rating ceiling, so derating for sustained operation is a matter of checking the actual transient energy and duty cycle against the thermal impedance curve.
