Transient protection for a 28V rail
Its 600W peak pulse power rating (10/1000µs waveform) and 45.4V clamping voltage at 13.8A peak pulse current give it the headroom to protect sensitive downstream components in industrial control, telecom, and general-purpose power supplies. The DO-214AA (SMB) surface-mount package fits standard pick-and-place and reflow processes.
What the 28V standoff and 600W pulse power mean for your BOM
The 28V reverse standoff voltage means this TVS will not conduct appreciable leakage on a 24V or 28V rail under normal operation — no wasted quiescent current. The 31.1V minimum breakdown voltage ensures the device starts clamping before the protected circuitry's absolute maximum rating is reached. The 600W peak pulse power at the standard 10/1000µs test waveform translates to a 13.8A peak pulse current capability; for a 28V rail, that handles most IEC 61000-4-5 surge levels at the secondary side of a power supply. If your application sees repetitive surges above this energy, you would step up to the 1500W SMCJ series in the same footprint family.
STMicroelectronics continues to manufacture the SMBJ and TRANSIL™ families as standard catalog parts. For BOM resilience, the SMBJ series is widely second-sourced by multiple manufacturers with identical DO-214AA footprint and matching 28V/600W ratings — qualifying an alternate now avoids a single-source exposure if allocation tightens.