{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451012.MR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451012.MR","canonicalUrl":"https://icboms.com/littelfuse-inc/0451012.MR","factsUrl":"https://icboms.com/api/mcp/products/0451012.MR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse Inc. NANO²® 451 series, Board Mount (Cartridge Style Excluded), Fast Blow, 12 A, 65 V AC/DC, 50 A breaking capacity, Surface Mount, 2-SMD Square End Block, Tape & Reel.","salesMarkdown":"## Obsolete — last-time-buy window closed The 0451012.MR: Sourcing now runs through independent surplus and broker channels. Availability is lot-specific and confirmed at RFQ; date-code provenance and traceability documentation should be verified before committing to a BOM line. ## 12 A fast-blow fuse, 65 V rating, 50 A breaking capacity Rated 12 A continuous at 65 V AC or DC, this surface-mount fuse clears overcurrents with a fast-blow response — the melting I²t of 47.97 A²s defines the energy let-through before the element opens. For a 12 A rail, that I²t is low enough to protect downstream semiconductors from short-circuit thermal stress, but the 50 A breaking capacity at rated voltage means the fuse must see a prospective fault current below that ceiling; higher available fault current requires an upstream current-limiting device. ## Surface-mount footprint and thermal envelope Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the fuse sits flat on the PCB with end-cap terminations — no through-hole leads, so the reflow profile must match the solder paste and the pad geometry on the board. Tape & Reel packaging supports automated pick-and-place assembly; the square end-block body is self-aligning during reflow, but the small 2.69 mm height means the fuse is not a candidate for hand-soldering touch-up without risk of thermal damage to the element. ## Approvals and compliance baseline CSA and UL approval agency listing means the fuse carries safety certification for North American and Canadian markets — UL 248-14 for supplemental fuses. RoHS and REACH compliance documentation is available from the manufacturer; the part is lead-free and does not contain the restricted substances under the current EU directives.","metaTitle":"Littelfuse 0451012.MR NANO² 451 Fuse, 12 A, 65 V, Fast Blow","metaDescription":"Littelfuse 0451012.MR NANO²® 451 fast-blow fuse, 12 A, 65 V AC/DC, 50 A breaking capacity, surface mount.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Circuit Protection"],"specifications":{"Mfr":"Littelfuse Inc.","Color":"-","Series":"NANO²® 451","Package":"Tape & Reel (TR)","Fuse Type":"Board Mount (Cartridge Style Excluded)","Melting I²t":"47.97","Mounting Type":"Surface Mount","Response Time":"Fast Blow","Package / Case":"2-SMD, Square End Block","Product Status":"Obsolete","Approval Agency":"CSA, UL","lifecycle_stage":"unknown","Size / Dimension":"0.240\\\" L x 0.106\\\" W x 0.106\\\" H (6.10mm x 2.69mm x 2.69mm)","DC Cold Resistance":"0.0049 Ohms","Voltage Rating - AC":"65 V","Voltage Rating - DC":"65 V","Current Rating (Amps)":"12 A","Operating Temperature":"-55°C ~ 125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.2800","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/2e33e7b2503f3f5110226be89402b64a.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What compliance documentation does Littelfuse provide for 0451012.MR?","answer":"The fuse carries CSA and UL safety approvals. RoHS and REACH compliance documentation is available from Littelfuse; the part is lead-free and meets current EU substance restrictions."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451012.MR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451012.MR when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-20T14:34:45.345Z","lastPublished":"2026-07-20T14:34:45.345Z","indexable":true}}