{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM4T30AY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM4T30AY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM4T30AY","factsUrl":"https://icboms.com/api/mcp/products/SM4T30AY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM4T30AY, Automotive AEC-Q101 TRANSIL™ TVS diode, 400W peak pulse power, 26V reverse standoff voltage, 53.5V clamping, unidirectional, DO-214AC SMA package.","salesMarkdown":"## What the 26V standoff and 53.5V clamp mean for a 24V automotive bus Its 26V reverse standoff voltage sits just above a nominal 24V supply rail, so the diode stays out of conduction under normal operating conditions. When a transient exceeds the 28.9V minimum breakdown threshold, the device clamps the surge to a maximum of 53.5V at the rated peak pulse current of 43A (8/20 µs waveform). That clamping voltage is the number to check against the downstream IC's absolute-maximum input rating—if the ECU's regulator or transceiver can survive 53.5V for the pulse duration, this part provides adequate protection. ## 400W peak pulse power—what it handles and what it doesn't For an automotive 24V system, this covers most inductive-load dump and ISO 7637-2 pulse 5a scenarios, but a direct lightning strike or a long-duration alternator load dump may exceed the device's safe operating area. The 43A peak pulse current at 8/20 µs gives a fast-rise surge benchmark for ESD and short-circuit transients. Power line protection is explicitly not supported, so this part should be used on signal or low-power supply lines, not on the main battery or alternator bus. ## AEC-Q101 and the SMA package: what the qualification buys you AEC-Q101 qualification is the automotive-grade baseline for discrete semiconductors. It means the SM4T30AY has passed the stress tests (HTRB, H3TRB, TC, etc.) required for use in under-hood and chassis-domain electronics, and the supplier can provide PPAP documentation on request.","metaTitle":"SM4T30AY 400W TVS Diode, AEC-Q101, 26V Standoff, SMA","metaDescription":"STMicroelectronics SM4T30AY automotive TVS diode, AEC-Q101 qualified, 400W peak pulse power, 26V reverse standoff, 53.5V clamping in DO-214AC SMA.","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":"SM4T30","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)":"28.9V","Voltage - Clamping (Max) @ Ipp":"53.5V","Voltage - Reverse Standoff (Typ)":"26V","Current - Peak Pulse (10/1000µs)":"43A (8/20µs)"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.4658","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/45721247f0377ca5ff3983c35eddc2fa.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is SM4T30AY AEC-Q101 qualified?","answer":"Yes, the SM4T30AY is part of the Automotive, AEC-Q101, SM4TY, TRANSIL™ series. This qualification covers the stress and reliability tests required for automotive-grade applications, and PPAP documentation is available from STMicroelectronics."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM4T30AY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM4T30AY 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}}