What the SM15T150CA protects and how it fits
The STMicroelectronics SM15T150CA is a 1500W bidirectional TVS diode from the TRANSIL™ family, designed to clamp transients on general-purpose power and signal lines. Its 128V reverse standoff voltage means it stays transparent below that DC level, then breaks down at a minimum of 143V and clamps at 265V maximum under the 10/1000µs pulse waveform. The single bidirectional channel handles ±38A peak pulse current (8/20µs shape), making it a fit for 48V telecom rails, industrial DC buses, or any 128V-rated line that needs surge protection without polarity concerns.
Surface-mount DO-214AB SMC — footprint and reflow
The SM15T150CA comes in a DO-214AB SMC package, a standard surface-mount footprint for 1500W-class TVS diodes. It sits flat on the board with no through-hole leads, so reflow profile and solder paste volume follow the usual SMC guidelines.