{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"SM30T21AY","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"SM30T21AY","canonicalUrl":"https://icboms.com/stmicroelectronics/SM30T21AY","factsUrl":"https://icboms.com/api/mcp/products/SM30T21AY","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics SM30T21AY, Automotive AEC-Q101 TRANSIL™ TVS, 3000W peak pulse power, 18V reverse standoff, 29.2V clamp, unidirectional, DO-214AB SMC package, -55°C to 175°C.","salesMarkdown":"The STMicroelectronics SM30T21AY is a unidirectional TRANSIL™ TVS diode from the automotive SM30TY series, rated for 3000 W peak pulse power (10/1000 µs waveform) with a clamping voltage of 29.2 V at 102.7 A peak pulse current. This surge rating is sized for automotive load-dump and inductive-load transients on 12 V and 24 V vehicle electrical systems — the 18 V reverse standoff voltage sits comfortably above the nominal rail, so it does not conduct during normal operation, but the 20 V minimum breakdown ensures it triggers before the downstream electronics see damaging overvoltage. ## AEC-Q101 and the full temperature range The 175°C TJ(max) rating means the die can handle self-heating from repetitive surge events without derating prematurely — a common failure point for commercial-grade TVS diodes in a hot environment. For dual-sourcing or second-source qualification, the SM30TY series includes functionally similar variants at other voltage ratings; the base product number SM30T21 identifies the 18 V standoff / 20 V breakdown tier within the family. If the application needs a different clamp voltage, the same footprint and qualification level are available across the SM30TY range.","metaTitle":"STMicroelectronics SM30T21AY TVS Diode, 3000W, AEC-Q101","metaDescription":"STMicroelectronics SM30T21AY is a 3000W automotive TVS diode, AEC-Q101 qualified, unidirectional, 18V standoff, 29.2V clamp, SMC 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, SM30TY, TRANSIL™","Package":"Tape & Reel (TR); Cut Tape (CT)","Applications":"Automotive","Mounting Type":"Surface Mount","Package / Case":"DO-214AB, SMC","Product Status":"Active","lifecycle_stage":"eol_hot","Power - Peak Pulse":"3000W (3kW)","Base Product Number":"SM30T21","Operating Temperature":"-55°C~175°C(TJ)","Power Line Protection":"No","Capacitance @ Frequency":"-","Supplier Device Package":"SMC","Unidirectional Channels":"1","Voltage - Breakdown (Min)":"20V","Voltage - Clamping (Max) @ Ipp":"29.2V","Voltage - Reverse Standoff (Typ)":"18V","Current - Peak Pulse (10/1000µs)":"102.7A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.3500","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/c1da1532b421560a6148be51fb30338a.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Is SM30T21AY AEC-Q101 qualified?","answer":"Yes, the SM30T21AY is part of the Automotive, AEC-Q101 qualified SM30TY series, making it suitable for automotive-grade applications requiring documented reliability screening."},{"question":"What is the peak pulse power of SM30T21AY?","answer":"The SM30T21AY is rated for 3000 W peak pulse power (3 kW) per the 10/1000 µs waveform, with a clamping voltage of 29.2 V at 102.7 A peak pulse current."},{"question":"Is SM30T21AY bidirectional?","answer":"No, the SM30T21AY is a unidirectional TVS diode — it has one unidirectional channel, so it protects a single polarity rail. For bidirectional protection on AC or bipolar lines, a different part from the SM30TY series would be needed."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/SM30T21AY","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/SM30T21AY when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-16T15:42:48.066Z","lastPublished":"2026-07-16T15:42:48.066Z","indexable":true}}