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STMicroelectronics SM4T10CAY — Circuit Protection

STMicroelectronics SM4T10CAY TVS Diode, 400W, DO-214AC

MPNSM4T10CAY
Active

STMicroelectronics SM4T10CAY, Automotive, AEC-Q101, SM4TY, TRANSIL™, Zener, 400W, 8.5V standoff, 19.5V clamping, DO-214AC SMA, -55°C~150°C.

$0.6000Ref. price · indicative, final on quote
STMicroelectronics SM4T10CAY datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

SM4T10CAY specifications
ParameterValue
TypeZener
SeriesAutomotive, AEC-Q101, SM4TY, TRANSIL™
MountingSurface Mount
Voltage - breakdown9.4V
Voltage - clamping (Max) @ ipp19.5V
Voltage - reverse standoff8.5V
Current - peak pulse (10/1000μs)124A (8/20µs)
Power - peak pulse400W
Power line protectionNo
Operating temperature-55°C~150°C(TJ)
PackageTape & Reel (TR); Cut Tape (CT)
ApplicationsAutomotive
CaseDO-214AC, SMA
Bidirectional channels1

Product details

The STMicroelectronics SM4T10CAY is a bidirectional Zener TVS diode from the SM4TY TRANSIL™ series, rated for 400W peak pulse power (10/1000µs waveform). It clamps at 19.5V maximum and has an 8.5V reverse standoff voltage, making it a common choice for protecting 12V automotive electronics from load-dump and inductive surge events.

The 400W peak pulse power rating (10/1000µs) translates to a 124A peak pulse current capability at the 8/20µs waveform. For a 12V automotive system, the 8.5V standoff means the diode stays out of conduction during normal battery voltage swings (up to 16V during charge), but clamps hard at 19.5V when a transient hits. That clamping voltage is low enough to protect downstream ECUs and sensors without triggering a crowbar or blowing a fuse.

DO-214AC SMA — rework and assembly notes

For rework, the SMA body is small enough that a hot-air station at 300°C with a fine nozzle lifts the part cleanly without overheating the board.

Frequently asked questions

Is SM4T10CAY suitable for 12V automotive systems?

Yes. The 8.5V reverse standoff voltage and 19.5V clamping voltage are well matched to 12V automotive rails. The AEC-Q101 qualification and -55°C to 150°C temperature range cover under-hood and chassis environments.

Can SM4T10CAY replace SM4T10A?

The SM4T10CAY is the bidirectional version of the SM4T10A unidirectional part. Both share the same 400W rating, 8.5V standoff, and DO-214AC package. If your circuit requires bidirectional clamping (no polarity sensitivity), the SM4T10CAY is a drop-in replacement.