The STMicroelectronics SM6T24A is a 600W unidirectional TVS diode from the TRANSIL™ series, designed to clamp transient overvoltages on supply rails and signal lines in general-purpose equipment. It is a Zener-type device that responds to overvoltage events by shunting surge current to ground, protecting downstream semiconductors. Maximum clamping voltage at the peak pulse current of 93A (8/20µs waveform) is 42.8V, which defines the voltage the protected circuit sees during a surge. The DO-214AA (SMB) surface-mount package suits automated assembly for industrial control, telecom infrastructure, and power supply applications where board space is a constraint.
For a 20.5V rail, this provides substantial margin against typical industrial surges from inductive load switching or lightning-induced transients on external cables. The 93A peak pulse current at the 8/20µs waveform is the more relevant number for ESD and fast transient protection, as it reflects the diode's ability to handle high-current, short-duration events.
For BOM planning, this removes the obsolescence risk that drives urgent redesigns. No direct replacement or second-source alternate is recorded in the official cross-reference data, so the SM6T24A is the sole TRANSIL™ option at this voltage and power level in the DO-214AA package.