Protection window — how the clamping chain works
The 1.5SMC6.8A/TR13: For a 24 VDC rail the surge current into this clamp will be limited by the source impedance; the 144.8A peak pulse current figure tells you how much current the clamping action shunts before the downstream load sees the 10.5V ceiling.
Temperature and environment
The upper limit matters for enclosed panels without active cooling — a TVS that sits idle most of the time but absorbs a transient at 85°C ambient has less headroom than one at 25°C. Budget the derating path in the thermal model if the clamp is near other warm components. The DO-214AB SMC package is the standard high-power TVS footprint — the cathodic tab die-attach area drives the thermal resistance from junction to ambient. For hand-solder rework the tab requires reflow-profile attention, not just hand-iron work on the leads.
What this part is not
The spec flags Power Line Protection as No — this part is not a primary AC mains clamp. It is suited for secondary protection on DC rails, signal lines, and lower-energy transient paths. If the application is a 120/240VAC input rail you need the P6KE or 1.5KE series with appropriate surge ratings. Unidirectional only — one channel, one polarity. For bidirectional AC signal protection the 1.5SMC-C (biaxial) variant covers that use case in the same series footprint.