What the voltage ratings mean for automotive protection
The 1.5SMC68CAHE3/9AT: The 58.1 V reverse standoff is the bias the line sits at during normal operation — the TVS conducts no current here, so downstream circuitry sees only the nominal supply rail. The clamping ceiling is 92 V at the rated 16.3 A peak pulse (10/1000 µs waveform), which is the number the downstream IC's abs-max rating must stay below.
AEC-Q101 qualification and thermal margin
AEC-Q101 is the discrete-semiconductor counterpart to AEC-Q100 — it certifies the part passed temperature cycling, HTRB (high-temperature reverse bias), and mechanical stress screening at the component level, not just the device-level screen. That is the baseline an OEM auditor in Tier-1 automotive asks for. Budget the actual TJ against the clamping event power dissipation using the Zener impedance in the datasheet — at 16.3 A the clamping voltage is not zero, and the dissipation pulse must clear before TJ exceeds 150 °C.