Transient protection for a 85.5 V rail
The STMicroelectronics SM15T100A is a unidirectional TRANSIL™ TVS diode in the SM15T series, designed to clamp transients on a nominal 85.5 V supply rail. It delivers 1500 W of peak pulse power per the 10/1000 µs waveform, with a minimum breakdown voltage of 95 V and a maximum clamping voltage of 178 V at the rated peak pulse current of 56 A. The DO-214AB SMC package suits surface-mount assembly for general-purpose overvoltage protection in industrial, telecom, and automotive auxiliary circuits.
1500 W peak pulse — sizing the protection margin
The 1500 W rating (10/1000 µs) defines the energy the diode can absorb in a single pulse. For a 85.5 V rail, the 178 V clamping ceiling leaves headroom above the rail plus any normal ripple, so the protected downstream components see a hard voltage limit. The 56 A peak pulse current (8/20 µs waveform) gives the surge capacity for direct or indirect lightning strikes on exposed lines. Because power line protection is not enabled, this part is intended for signal or low-power supply rails, not mains-side AC input stages.
Temperature range and board-level fit
The SMC package footprint is standard for this power class; the cathode band identifies the unidirectional orientation.