33V rail clamp with 600W pulse rating
The SMBJ33A-13: Its 36.7V minimum breakdown voltage and 53.3V maximum clamping at 11.3A peak pulse current (10/1000µs waveform) mean this part catches overvoltage events before they reach downstream silicon — the clamp voltage sits well below the abs-max rating of common 40V-rated DC-DC converters and linear regulators on the same board.
Active production, DO-214AA footprint
Power line protection is marked No — this is a signal-rail or low-side supply clamp, not a primary AC mains protector.