SM4TY STMicroelectronics Diode (Diodes Moulded) In Stock
The SM4TY is an automotive-grade 400 W transient voltage suppressor (TVS) diode from STMicroelectronics in a compact SMA (DO-214AC) surface-mount package. It provides unidirectional overvoltage clamping rated for automotive load-dump and ESD events per AEC-Q101. Available from stock with worldwide shipping.
- Manufacturer
- STMicroelectronics
- Package
- Diodes Moulded
- Pin Count
- 2
- Lifecycle
- ACTIVE
- Datasheet
- SM4TY Datasheet PDF
- Category
- Diode
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 400 W peak pulse power dissipation capability for robust automotive load-dump transient protection
- AEC-Q101 automotive-qualified unidirectional TVS in compact SMA (DO-214AC) surface-mount package
- Fast sub-picosecond response time clamping voltage transients to protect sensitive 12 V automotive electronics
Applications
The SM4TY protects automotive electronic modules such as ECUs, body control units, and infotainment systems from destructive voltage transients generated by load-dump events up to 400 W on 12 V vehicle electrical systems. Its SMA package and surface-mount footprint make it easy to integrate close to protection-sensitive ICs on PCBs with limited board space. The AEC-Q101 qualification ensures long-term reliability in underhood and cabin environments subject to wide temperature swings from -40°C to 150°C.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What is the peak pulse power rating of the SM4TY TVS and what automotive transient event does it protect against?
The SM4TY is rated for 400 W peak pulse power dissipation, which is sufficient to clamp automotive load-dump transients up to approximately 40 V on a 12 V vehicle bus when a battery is disconnected from a running alternator. This 400 W rating directly corresponds to the ISO 7637-2 pulse 5a and 5b load-dump test conditions, protecting ECUs, sensor modules, and power supply inputs from destructive voltage spikes that can damage unprotected CMOS circuitry.
How does SM4TY's SMA package compare to larger TVS packages for space-constrained automotive PCB designs?
The SM4TY uses a SMA (DO-214AC) package measuring approximately 4.3 mm x 2.6 mm x 2.2 mm, which occupies roughly 60% less board area than SMB-package TVS diodes providing comparable 400 W protection. For compact automotive PCB layouts where board space near connector pins is limited to 10 mm² or less, the SMA footprint allows the SM4TY to be placed directly at transient entry points without requiring a dedicated large keepout zone.
When should SM4TY be used instead of a bidirectional TVS for automotive circuit protection?
SM4TY is a unidirectional TVS best suited for protecting circuits with DC supply rails where transients occur only in the positive direction, such as 12 V automotive battery lines supplying single-polarity loads. Bidirectional TVS devices are preferred for AC-coupled or data lines where transients appear in both polarities; however, for standard 12 V automotive power inputs protected against load-dump pulses above 13.5 V, the SM4TY's unidirectional 400 W clamping provides lower clamping voltage and better energy absorption than equivalent bidirectional alternatives.
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About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
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