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STMicroelectronics SMBJ48A-TR — Circuit Protection

STMicroelectronics SMBJ48A-TR TVS Diode, 600W, 48V Standoff

MPNSMBJ48A-TR
Active

STMicroelectronics SMBJ, TRANSIL™ series, TVS Zener diode, unidirectional, 48V reverse standoff, 53.3V breakdown, 77.4V clamp, 600W peak pulse, DO-214AA SMB, -55°C to 150°C.

$0.4300Ref. price · indicative, final on quote
STMicroelectronics SMBJ48A-TR datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

SMBJ48A-TR specifications
ParameterValue
TypeZener
SeriesSMBJ, TRANSIL™
MountingSurface Mount
Voltage - breakdown53.3V
Voltage - clamping (Max) @ ipp77.4V
Voltage - reverse standoff48V
Current - peak pulse (10/1000μs)8.1A
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

The 77.4 V clamping voltage at 8.1 A peak pulse current sets the upper bound the protected circuitry must survive.

Breakdown and standoff — sizing the protection window

The 48 V reverse standoff voltage is the maximum continuous DC voltage the diode can block without conducting — your rail must stay below this during normal operation. The 53.3 V minimum breakdown voltage is where the diode starts to avalanche; below that the protected bus is safe. With a 77.4 V clamp at 8.1 A, the device limits the spike to a level a downstream 80 V-rated MOSFET or DC-DC converter can withstand. The single unidirectional channel means polarity matters — cathode to the protected rail, anode to ground.

Temperature range and package — board-fit considerations

No power line protection (no internal series element), so it is a straight shunt to ground.

Frequently asked questions

What is the replacement or equivalent for SMBJ48A-TR?

The SMBJ48A-TR is an active standard part, so no direct replacement is needed. For a second-source option, look at other manufacturers' SMBJ48A parts in the same DO-214AA package — the SMBJ series is widely cross-sourced. Verify breakdown and clamping specs match your design margin.