1500 W peak pulse in a DO-214AB footprint
The 1.5SMC200AS_R1_00001: It clamps transients at 274 V max while the reverse standoff voltage sits at 171 V, meaning it stays out of the way of a 170 V nominal rail and only conducts when the surge pushes past the 190 V minimum breakdown threshold.
Clamping voltage and the protection window
The 274 V clamping voltage at 5.5 A peak pulse current defines the maximum voltage the downstream circuitry sees during a surge. For a 170 V bus, the 104 V margin between the rail and the clamp gives the secondary-side components headroom to survive without avalanche breakdown themselves. The -55°C to 150°C junction temperature range covers both cold-start and hot-soak conditions in outdoor or industrial enclosures. Power line protection is marked 'No', so this part is designed for signal or low-voltage DC bus protection, not for direct AC mains clamping.