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STMicroelectronics SM30T28CAY — Circuit Protection

STMicroelectronics SM30T28CAY TVS Diode, 3000W Bidirectional

MPNSM30T28CAY
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STMicroelectronics SM30T28CAY, Automotive AEC-Q101 TRANSIL™ bidirectional TVS diode, 3000W peak pulse power, 24V reverse standoff, 38.9V clamping, DO-214AB SMC surface mount.

$1.5000Ref. price · indicative, final on quote
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

SM30T28CAY specifications
ParameterValue
TypeZener
SeriesAutomotive, AEC-Q101, SM30TY, TRANSIL™
MountingSurface Mount
Voltage - breakdown26.7V
Voltage - clamping (Max) @ ipp38.9V
Voltage - reverse standoff24V
Current - peak pulse (10/1000μs)77.1A
Power - peak pulse3000W (3kW)
Power line protectionNo
Operating temperature-55°C~175°C(TJ)
PackageTape & Reel (TR); Cut Tape (CT)
ApplicationsAutomotive
CaseDO-214AB, SMC
Bidirectional channels1

Product details

3000W bidirectional TVS for 24V automotive rails

The STMicroelectronics SM30T28CAY is a bidirectional Zener-type TVS diode from the TRANSIL™ series, rated for 3000W peak pulse power (10/1000µs waveform) and qualified to AEC-Q101 for automotive applications. It protects a 24V nominal rail with a reverse standoff voltage of 24V, a minimum breakdown of 26.7V, and a maximum clamping voltage of 38.9V at the 77.1A peak pulse current. The single bidirectional channel makes it suitable for protecting AC-coupled or bipolar signal lines where polarity-independent clamping is required.

What the 3000W rating means for the BOM

The 3000W peak pulse power rating defines the energy-handling capability for a single 10/1000µs surge event. For a 24V system, this translates to a clamping voltage of 38.9V at the rated current, which keeps downstream components within their safe operating area during load-dump or inductive-load transients. The 77.1A peak pulse current gives a direct check against the expected surge current from the system's worst-case transient — if the calculated surge exceeds this figure, a higher-power device or external protection network is needed. The surface-mount assembly keeps the board compatible with reflow processes common in automotive ECU production.

The -55°C low end also supports cold-crank and arctic-condition operation.

Frequently asked questions

Is SM30T28CAY a bidirectional TVS diode?

Yes, it has one bidirectional channel, meaning it clamps both positive and negative transients symmetrically — useful for AC signal lines or bipolar power rails where polarity-independent protection is needed.

What are the replacements for SM30T28CAY?

The base product number SM30T28 covers a family of AEC-Q101 qualified TVS diodes in the SMC package. Pin-compatible alternatives within the same TRANSIL™ series share the same footprint and voltage ratings, allowing dual-sourcing for supply resilience.