{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM4T33AY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM4T33AY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM4T33AY","factsUrl":"https://icboms.com/api/mcp/products/SM4T33AY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM4T33AY, Automotive AEC-Q101 Zener TVS Diode, 400W Peak Pulse Power, 28V Reverse Standoff, 31.1V Breakdown Min, 59V Clamping, DO-214AC SMA Package, -55°C to 150°C.","salesMarkdown":"## What this TVS diode protects and where it goes The STMicroelectronics SM4T33AY is a unidirectional Zener-type transient-voltage-suppression (TVS) diode from the SM4TY series, rated for a peak pulse power of 400W. The DO-214AC (SMA) surface-mount package suits automated assembly flows common in high-volume automotive PCB production. ## 400W peak pulse — what that 10/1000 µs rating means for your rail For the shorter 8/20 µs waveform (often used to represent ESD or faster transients), the device can handle a peak pulse current of 39A. The 28V reverse standoff voltage means this diode will not conduct appreciably below that rail voltage, so a 24V or 28V nominal supply bus stays protected without leakage issues during normal operation. The 59V clamping voltage is the maximum voltage the load sees during the transient — the load's own voltage tolerance must stay above that ceiling to avoid secondary damage. Because the part is a Zener-type (not an avalanche type with a different snap-back characteristic), the clamping voltage versus current curve is relatively flat, giving predictable protection across the current range. ## DO-214AC SMA — footprint and assembly notes The package is the standard DO-214AC (SMA) two-lead surface-mount package. The cathode band identifies the unidirectional orientation. The SM4T33AY is a current-production part from STMicroelectronics, available through independent distribution channels. For a BOM line requiring a 28V rail clamp with automotive qualification, this diode is a direct fit. The part is not subject to a last-time-buy or end-of-life notice, so it can be specified for production runs without a short-term obsolescence review.","metaTitle":"STMicroelectronics SM4T33AY Zener TVS Diode, 400W, DO-214AC","metaDescription":"STMicroelectronics SM4T33AY automotive AEC-Q101 Zener TVS diode, 28V reverse standoff, 400W peak pulse, DO-214AC SMA package.","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":"SM4T33","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)":"31.1V","Voltage - Clamping (Max) @ Ipp":"59V","Voltage - Reverse Standoff (Typ)":"28V","Current - Peak Pulse (10/1000µs)":"39A (8/20µs)"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.8900","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/45721247f0377ca5ff3983c35eddc2fa.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is SM4T33AY automotive grade?","answer":"Yes, the SM4T33AY is AEC-Q101 qualified and belongs to the Automotive series. It is rated for the -55°C to 150°C operating temperature range, suitable for under-hood and other harsh automotive environments."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM4T33AY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM4T33AY 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}}