{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM4T12CAY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM4T12CAY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM4T12CAY","factsUrl":"https://icboms.com/api/mcp/products/SM4T12CAY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM4T12CAY, Automotive AEC-Q101 TRANSIL™ TVS diode, bidirectional, 400W peak pulse power, 10V reverse standoff, DO-214AC (SMA) package, surface mount.","salesMarkdown":"## What this TVS diode does on the board It handles a peak pulse power of 400 W (10/1000 µs waveform) and clamps at 21.7 V max at the rated peak pulse current of 106 A (8/20 µs waveform). The breakdown voltage range starts at 11.1 V min, so it triggers before the protected circuitry sees damaging overvoltage. For a 10 V rail, that translates to a peak current capability of 106 A under the 8/20 µs waveform used for ESD and surge testing. The 21.7 V clamping voltage tells you the maximum voltage the downstream components must survive. If your load has a 20 V absolute maximum on the supply pin, this part holds the clamp below that threshold — but check the margin at your specific operating current. With a single bidirectional channel, the SM4T12CAY clamps positive and negative transients symmetrically. That simplifies BOM and layout on AC-coupled lines or signal pairs where polarity isn't fixed. The reverse standoff voltage is 10 V — the rail voltage it leaves alone during normal operation. No power line protection (it's not designed for continuous overvoltage), so it's a pure transient suppressor. ## DO-214AC (SMA) — rework and footprint Housed in a DO-214AC (SMA) surface-mount package, the SM4T12CAY is a standard two-terminal part. The SMA body is small enough for dense layouts but large enough to hand-rework with a hot-air station without lifting the pad — the thermal mass is manageable. Orientation is straightforward: the cathode band marks the reference for the unidirectional version, but on this bidirectional part the marking identifies the part number, not polarity. The package footprint matches standard SMA land patterns; no special pad geometry needed beyond the datasheet recommendation. No last-time-buy or obsolescence risk to budget around.","metaTitle":"STMicroelectronics SM4T12CAY TVS Diode, 400W, Bidirectional","metaDescription":"STMicroelectronics SM4T12CAY bidirectional TVS diode, 400W peak pulse power, 10V reverse standoff, AEC-Q101 qualified. Active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Protection"],"specifications":{"Mfr":"STMicroelectronics","Type":"Zener","Series":"Automotive, AEC-Q101, SM4TY, TRANSIL™","Package":"Tape & Reel (TR); Cut Tape (CT)","Applications":"Automotive","Mounting Type":"Surface Mount","Package / Case":"DO-214AC, SMA","Product Status":"Active","lifecycle_stage":"eol_hot","Power - Peak Pulse":"400W","Base Product Number":"SM4T12","Operating Temperature":"-55°C~150°C(TJ)","Power Line Protection":"No","Bidirectional Channels":"1","Capacitance @ Frequency":"-","Supplier Device Package":"SMA (DO-214AC)","Voltage - Breakdown (Min)":"11.1V","Voltage - Clamping (Max) @ Ipp":"21.7V","Voltage - Reverse Standoff (Typ)":"10V","Current - Peak Pulse (10/1000µs)":"106A (8/20µs)"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.6300","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/45721247f0377ca5ff3983c35eddc2fa.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is SM4T12CAY automotive qualified (AEC-Q101)?","answer":"Yes, the SM4T12CAY is AEC-Q101 qualified as part of the Automotive SM4TY series."},{"question":"What is the SM4T12CAY peak pulse power rating?","answer":"The SM4T12CAY is rated for 400 W peak pulse power under the 10/1000 µs waveform. Under the 8/20 µs waveform, it handles a peak pulse current of 106 A, clamping at 21.7 V max."},{"question":"Is the SM4T12CAY a bidirectional or unidirectional TVS diode?","answer":"The SM4T12CAY is a bidirectional TVS diode with a single channel. It clamps both positive and negative transients symmetrically, with a 10 V reverse standoff voltage."},{"question":"Is SM4T12CAY RoHS compliant?","answer":"The SM4T12CAY is listed as part of the STMicroelectronics TRANSIL™ series, which is generally RoHS compliant. Verify the specific date code and packaging against the manufacturer's compliance declaration for your batch."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM4T12CAY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM4T12CAY when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:49:49.435Z","lastPublished":"2026-08-11T15:49:49.435Z","indexable":true}}