{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM4T50AY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM4T50AY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM4T50AY","factsUrl":"https://icboms.com/api/mcp/products/SM4T50AY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM4T50AY automotive TVS zener diode, 400W peak pulse power, 43V reverse standoff, 91V clamping, single unidirectional channel, AEC-Q101 qualified, DO-214AC (SMA) surface mount, -55°C to 150°C.","salesMarkdown":"## 400W TVS in an SMA footprint — the automotive-grade clamp for 48V rails The STMicroelectronics SM4T50AY is a single-channel unidirectional TVS zener diode rated for 400W peak pulse power (10/1000µs waveform), packaged in a DO-214AC (SMA) surface-mount case. ## 43V standoff, 91V clamp — where the protection window lands The reverse standoff voltage is 43V, meaning the device does not conduct appreciably below that rail level. Breakdown occurs at a minimum of 47.8V, and the clamping voltage is held to 91V at the rated peak pulse current of 25A (8/20µs waveform). For a 48V nominal bus — common in automotive start-stop and mild-hybrid systems — this clamp window catches transients before they reach downstream silicon without nuisance triggering on normal ripple. ## AEC-Q101 and the full temperature envelope AEC-Q101 qualification covers the device-level stress tests that automotive Tier-1s require: high-temperature reverse bias, temperature cycling, and humidity bias. The -55°C to 150°C operating junction range means this part survives cold-crank at -40°C and under-hood soak at 125°C ambient with margin. No power line protection feature is integrated — this is a pure transient clamp, not a crowbar or overvoltage regulator.","metaTitle":"STMicroelectronics SM4T50AY TVS Diode, 400W, AEC-Q101, SMA","metaDescription":"STMicroelectronics SM4T50AY automotive TVS zener diode, 400W peak pulse, 43V standoff, 91V clamping, AEC-Q101, SMA package, -55°C to 150°C.","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":"SM4T50","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)":"47.8V","Voltage - Clamping (Max) @ Ipp":"91V","Voltage - Reverse Standoff (Typ)":"43V","Current - Peak Pulse (10/1000µs)":"25A (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":"What is the SM4T50AY replacement or equivalent part?","answer":"No official replacement or pin-compatible equivalent is listed by STMicroelectronics. The SM4T50 family shares the same base product number but each voltage variant is a distinct device. For a drop-in replacement, source the exact SM4T50AY order code."},{"question":"Where can I download the SM4T50AY datasheet?","answer":"The datasheet is available from STMicroelectronics directly or through the product page on this site. The key specifications — 400W peak pulse, 43V standoff, 91V clamping, AEC-Q101, SMA package — are summarized above."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM4T50AY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM4T50AY 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}}