AEC-Q101 — the automotive reliability gate
AEC-Q101 qualification means the SMBJ70CAQ-13-F passed the stress tests required for automotive-grade discrete semiconductors: high-temperature reverse bias (HTRB), temperature cycling, and ESD robustness per the AEC-Q101 rev D test suite. The -55°C to 150°C junction temperature range covers the full automotive envelope — under-hood ambient at 125°C plus self-heating from the 600 W pulse still leaves margin before the Tj max.
600 W peak pulse — what the rating actually means
The 70 V standoff voltage (Vrwm) is the maximum DC rail the TVS can sit across without conducting leakage current.
Bidirectional — one die, both polarities
The SMB (DO-214AA) footprint is the standard for 600 W class TVS diodes. The copper tab on the cathode side conducts heat into the PCB pad — a 12 mm² copper area on the top layer keeps the junction temperature rise within the derating curve for repetitive surges.