1500 W bidirectional transient suppressor for 12 V rails
The STMicroelectronics SM15T15CA is a bidirectional Zener TVS diode from the TRANSIL™ family, designed to clamp voltage transients on DC power and signal lines. Its 1500 W peak pulse power rating (10/1000 µs waveform) handles surges from inductive load switching, lightning-induced transients, and ESD events in general-purpose equipment. The device is bidirectional, so a single part protects both polarities on a 12.8 V nominal rail, clamping at 27.2 V maximum. The DO-214AB (SMC) surface-mount package suits automated assembly for medium- to high-volume production.
The 12.8 V reverse standoff voltage is the maximum DC or peak AC voltage the TVS can block without conducting appreciable leakage. For a nominal 12 V supply (automotive battery, industrial 12 V rail), this provides margin for steady-state tolerances and ripple. Breakdown is guaranteed at 14.3 V minimum, so the device stays off during normal operation and only avalanches when a transient pushes the line above that threshold. The 27.2 V clamping voltage at the peak pulse current of 368 A (8/20 µs waveform) defines the maximum voltage the downstream circuitry sees during a surge — a key parameter for selecting the TVS against the protected IC's absolute maximum rating.
The 150°C upper limit allows operation in engine bays, outdoor telecom cabinets, and factory-floor enclosures without derating the peak pulse power at elevated temperatures — though the 1500 W rating is specified at 25°C and derates linearly above that. The wide temperature range also simplifies qualification across multiple product platforms sharing a common BOM.