600W peak pulse, 26V rail – where this TVS fits
The SMBJ26CAE3/TR13: Its 26V reverse standoff voltage means it sits across a 24V nominal rail without conducting leakage until the transient exceeds 28.9V breakdown. The 42.1V clamping voltage limits the spike the downstream IC sees. No need to series two unidirectional parts.
Clamping voltage and peak current – the margin check
The 42.1V clamp at 14.2A peak pulse current is the worst-case voltage the protected circuit sees. Compare that against the absolute-maximum rating of the downstream IC — a 40V-rated switching regulator has 2.1V of headroom; a 36V-rated part does not. The 600W peak pulse rating assumes a 10/1000 µs waveform. For shorter pulses (e.g. 8/20 µs) the peak power capability is higher — the datasheet derating curve shows the multiplier, but the 600W figure is the baseline for BOM comparison.
Microchip lists this part as Active. Supplied on tape & reel — standard for automated pick-and-place. The - suffix indicates RoHS-compliant and halogen-free construction.