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STMicroelectronics SM6T39A — Circuit Protection

SM6T39A STMicroelectronics TRANSIL TVS, 600W, 33.3V Standoff

MPNSM6T39A
Active

STMicroelectronics SM6T39A, TRANSIL™ series, 600W unidirectional TVS diode, 33.3V reverse standoff, 69.7V clamp, DO-214AA (SMB), surface mount, -55°C to 150°C.

$0.5500Ref. price · indicative, final on quote
STMicroelectronics SM6T39A datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

SM6T39A specifications
ParameterValue
TypeZener
SeriesSM6T, TRANSIL™
MountingSurface Mount
Voltage - breakdown37.1V
Voltage - clamping (Max) @ ipp69.7V
Voltage - reverse standoff33.3V
Current - peak pulse (10/1000μs)57A (8/20µs)
Power - peak pulse600W
Power line protectionNo
Operating temperature-55°C ~ 150°C (TJ)
PackageTape & Reel (TR) Cut Tape (CT)
ApplicationsGeneral Purpose
CaseDO-214AA, SMB
Unidirectional channels1

Product details

600W unidirectional transient suppressor for 33.3V rails

The STMicroelectronics SM6T39A is a 600W unidirectional TRANSIL™ TVS diode in a DO-214AA (SMB) surface-mount package, designed to clamp transients on DC power rails and signal lines with a 33.3V reverse standoff voltage.

Voltage thresholds and clamping margin

Three voltage numbers define where this part fits on a rail. The 33.3V reverse standoff is the maximum DC voltage the diode will not conduct at — a 24V nominal bus with 30% tolerance sits safely below it. Breakdown starts at 37.1V minimum, and clamping hits 69.7V maximum at the rated 57A peak pulse current. That 69.7V clamp is the voltage the protected circuitry must survive for the pulse duration; a 60V-rated downstream regulator would need a second stage or a higher-voltage part upstream.

Active lifecycle and BOM planning

The TRANSIL series has broad distribution coverage, which supports multi-source procurement without sole-source exposure.

Frequently asked questions

What is SM6T39A used for?

It is a 600W unidirectional transient voltage suppressor for general-purpose overvoltage protection on DC power rails and signal lines with a 33.3V standoff voltage.

Is SM6T39A unidirectional or bidirectional?

The SM6T39A is a unidirectional TVS diode, with one protection channel. It conducts in one direction only, making it suitable for DC rail protection where polarity is fixed.

What is the equivalent or replacement for SM6T39A?

The SM6T39A is an active part with no official successor listed. For a pin-compatible alternative in the same TRANSIL family, a part with the same DO-214AA footprint and a 33.3V standoff voltage from the SM6T series would be the closest functional match, but no specific order code is cited as a direct replacement.