What the 1.5SMCJ28 is and what it protects
It clamps voltage spikes on a line before they reach downstream circuits — the standoff voltage of 28 V sets the continuous working plane, the minimum breakdown of 31.1 V is where the device begins conducting, and the 50 V clamping ceiling is the maximum the downstream load sees at the rated 30 A peak pulse current.
Peak pulse and clamping mechanics
The 10/1000 µs waveform rating is the standard IEC 61000-4-5 surge test shape — 10 µs rise, 1000 µs fall. At that pulse shape the diode dissipates 1.5 kW without entering thermal runaway. The 30 A peak pulse rating is the current the clamping action handles at the specified waveform; the actual let-through voltage is bounded by the 50 V ceiling at that current level. For a 28 V rail, a 31.1 V minimum breakdown gives roughly 11 % headroom above the working voltage before the device starts conducting — a conservative ratio that avoids false triggering under normal line noise. Once a surge exceeds 31.1 V, the diode avalanches and clamps, clamping voltage is held to 50 V max.
Sourcing and lifecycle posture
Sourced to order through independent distribution against BOM quantities — availability and lead time confirmed at RFQ. No official successor or cross-reference is documented in the Diotec family record for this specific order code.