{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451012.NR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451012.NR","canonicalUrl":"https://icboms.com/littelfuse-inc/0451012.NR","factsUrl":"https://icboms.com/api/mcp/products/0451012.NR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, Board Mount SMD Fuse, 0451012.NR, 12 A, 65 VAC/DC, Fast Blow, 50 A breaking capacity, 2-SMD square end block, Tape & Reel.","salesMarkdown":"## 12 A fast-blow SMD fuse — what the ratings mean for the repair bench The 0451012.NR is a Littelfuse NANO²® 451 series board-mount SMD fuse, rated 12 A continuous at 65 VAC or 65 VDC. The fast-blow response means it clears on moderate overcurrents quickly — the 47.97 A²s melting I²t tells you it handles brief inrush without nuisance opening, but a sustained overload near 20 A will trip it in under a second. The 50 A breaking capacity at rated voltage is the key fit check: this fuse safely interrupts faults up to 50 A. If your board's available fault current exceeds that — say from a stiff 65 VDC supply — you need a higher-interrupting fuse or a current-limiting element upstream. ## Obsolete — sourcing the 0451012.NR now Littelfuse lists the 0451012.NR as obsolete. No official successor order code is recorded. For a board in the field that needs this exact footprint — 0.240\" x 0.106\" x 0.106\" (6.10 mm x 2.69 mm x 2.69 mm) 2-SMD square end block — the replacement path is through independent surplus or last-time-buy inventory. We source this part to order against an RFQ. ## Temperature range and approvals The 0.0049 Ω DC cold resistance means the voltage drop at 12 A is under 60 mV — negligible for most low-voltage rails. CSA and UL approved — the approvals cover the safety interrupt ratings for North American and Canadian installations.","metaTitle":"0451012.NR Littelfuse NANO² 451 12A 65V Fast-Blow SMD Fuse","metaDescription":"0451012.NR Littelfuse NANO² 451 SMD fuse, 12A, 65VAC/DC, fast-blow, 50A breaking capacity. Obsolete — sourced to order against RFQ. UL/CSA approved.","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":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the closest pin-compatible alternative to 0451012.NR?","answer":"No official pin-compatible successor is recorded from Littelfuse. The NANO² 451 series had multiple current ratings in the same 2-SMD square end block footprint, but a direct drop-in replacement at 12 A fast-blow with the same 65 V rating and 50 A breaking capacity would need to be verified against the board's available fault current and I²t tolerance."},{"question":"What compliance documentation does Littelfuse provide for 0451012.NR?","answer":"The fuse carries CSA and UL approvals. RoHS and REACH compliance status is typical for this series but should be confirmed on the specific date code lot at RFQ."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451012.NR","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.NR 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}}