{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM4T10AY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM4T10AY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM4T10AY","factsUrl":"https://icboms.com/api/mcp/products/SM4T10AY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM4T10AY, Automotive Grade TVS Zener Diode, 400W Peak Pulse Power, 8.5V Reverse Standoff, 9.4V Breakdown Min, Unidirectional, DO-214AC (SMA) Package, AEC-Q101 Qualified, -55°C to 150°C.","salesMarkdown":"## What this TVS protects and why it is rated for automotive The SM4T10AY is a unidirectional TVS Zener diode from STMicroelectronics, designed to clamp voltage transients on DC power rails and signal lines. It is rated for 400W peak pulse power (10/1000µs waveform) and offers a reverse standoff voltage of 8.5V, meaning it sits across a 5V or 8V rail without conducting until a transient pushes it past the 9.4V minimum breakdown threshold. The clamping voltage is held to 19.5V maximum at the peak pulse current of 124A (8/20µs). That temperature range covers under-hood electronics, engine bay sensors, and any outdoor industrial enclosure where the ambient can spike. The DO-214AC (SMA) surface-mount package is standard for this power class and fits automated assembly lines without special handling beyond normal MSL precautions. The 8.5V reverse standoff voltage is the maximum DC voltage the part can block without conducting. If your rail is 5V or 8V nominal, this part stays invisible. Once a transient pushes the line above 9.4V (the minimum breakdown), the Zener avalanches and clamps the voltage to 19.5V maximum at the rated peak current. That 19.5V ceiling protects downstream silicon rated for, say, 20V or 24V absolute maximum. The 400W peak pulse power rating is based on a 10/1000µs waveform. For shorter pulses like 8/20µs (common in ESD or lightning surge testing), the peak current capability is higher — 124A in this case. If your application calls for repetitive surges or longer pulse widths, derate the power per the thermal curve in the datasheet; the junction temperature rating of 150°C is the hard limit. ## Package, storage, and assembly notes The SM4T10AY comes in a DO-214AC (SMA) package, supplied on Tape & Reel or Cut Tape. It is a surface-mount device, so standard reflow profiles for SMA work. The part is unidirectional — one channel, cathode band marked. If your circuit needs bidirectional protection, you will need two devices back-to-back or a different order code. Store the reels dry. SMA parts are generally MSL 1, but verify the date code on the reel label — if the moisture barrier bag has been open longer than the floor life, bake before reflow per J-STD-033.","metaTitle":"SM4T10AY STMicroelectronics Automotive TVS Diode, 400W","metaDescription":"SM4T10AY is an AEC-Q101 qualified automotive TVS Zener diode from STMicroelectronics.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Protection"],"specifications":{"Mfr":"STMicroelectronics","Type":"Zener","Grade":"Automotive","Series":"*","Package":"Tape & Reel (TR) Cut Tape (CT)","Applications":"-","Mounting Type":"Surface Mount","Qualification":"AEC-Q101","Package / Case":"DO-214AC, SMA","Product Status":"Active","lifecycle_stage":"eol_hot","Power - Peak Pulse":"400W","Base Product Number":"SM4T10","Operating Temperature":"-55°C ~ 150°C (TJ)","Power Line Protection":"No","Capacitance @ Frequency":"-","Supplier Device Package":"SMA (DO-214AC)","Unidirectional Channels":"1","Voltage - Breakdown (Min)":"9.4V","Voltage - Clamping (Max) @ Ipp":"19.5V","Voltage - Reverse Standoff (Typ)":"8.5V","Current - Peak Pulse (10/1000µs)":"124A (8/20µs)"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.6400","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/45721247f0377ca5ff3983c35eddc2fa.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is SM4T10AY AEC-Q101 qualified?","answer":"Yes, the SM4T10AY carries AEC-Q101 qualification, making it suitable for automotive applications that require stress-tested, reliable semiconductor components."},{"question":"Is SM4T10AY a bidirectional TVS diode?","answer":"No, the SM4T10AY is a unidirectional TVS Zener diode. It has one channel and protects against transients in one polarity. For bidirectional protection, use two devices back-to-back or select a bidirectional TVS."},{"question":"What is the SM4T10AY replacement or equivalent?","answer":"No official replacement or successor is listed. For a second-source, look for AEC-Q101 qualified TVS diodes in the same DO-214AC package with 8.5V standoff and 400W rating from other manufacturers, but verify pin compatibility and electrical characteristics against your specific transient requirements."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM4T10AY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM4T10AY when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-16T15:19:50.115Z","lastPublished":"2026-07-16T15:19:50.115Z","indexable":true}}