Automotive-grade clamp for 33V rails
The SMAJ33AQ-13-F: This means a 24V or 28V nominal bus — common in automotive power distribution — sees no leakage during normal operation, and the clamp engages before the downstream silicon sees a damaging overvoltage. The 7.5A peak pulse current figure is the current through the device at the clamping voltage — it is the surge the diode can safely shunt to ground.
AEC-Q101 — the qualification an OEM auditor expects
AEC-Q101 qualification means this TVS has passed the automotive discrete semiconductor stress tests: temperature cycling, high-temperature reverse bias, and ESD robustness, among others. For a Tier-1 supplier submitting a PPAP package, the SMAJ33AQ-13-F carries the grade documentation the customer's quality team will ask for.
DO-214AC (SMA) — board-fit and thermal note
The DO-214AC (SMA) package is a standard surface-mount footprint for TVS diodes. For the 400W pulse rating, a pad of at least 30 mm² on a standard FR4 board is typical to keep the die temperature within the 150°C limit during repetitive surges. The part is unidirectional (one channel), so the cathode is marked and the anode is on the opposite end.