210V standoff, 340V clamping — the TVS protection window
The 1.5SMCJ210A_R1_00001: A faster edge or a higher-energy surge consumes more of the 1.5 kW peak-pulse rating budget than a slow, long-duration event.
Unidirectional Zener TVS — type and series positioning
This is a unidirectional Zener-based TVS (Transient Voltage Suppressor), not a power-line protection module — it clamps a single polarity and is designed for DC rails or the positive half-cycle of an AC line. The 1.5SMCJ series positions it as a 1.5 kW peak-pulse device in the standard SMC body, which is the mid-range surge-handling class between the 400W and 3 kW families in most manufacturer portfolios. Keeping the Tj well below 150°C under fault is the layout and airflow constraint the designer owns.
SMC (DO-214AB) surface-mount — what it connects to
The SMC (DO-214AB) package is the common larger-SMD TVS footprint — the three-terminal barrel shape mounts to a recommended pad layout that ties the cathode to the protected rail and the anode to ground. Available in Tape & Reel and Cut Tape packaging, which determines the pick-and-place setup for high-volume assembly versus prototype rework quantities.