{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451.375NR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451.375NR","canonicalUrl":"https://icboms.com/littelfuse-inc/0451.375NR","factsUrl":"https://icboms.com/api/mcp/products/0451.375NR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, board mount (cartridge style excluded), surface mount, fast blow, 375 mA, 125 V AC/DC, 50 A breaking capacity, 2-SMD square end block package, 0451.375NR.","salesMarkdown":"## What the 50 A breaking capacity means for board-level protection The 0451.375NR is a Littelfuse NANO² 451 series fast-blow fuse rated 375 mA at 125 V AC or DC, with a breaking capacity of 50 A at rated voltage. That 50 A interrupt rating means it can safely clear a fault current up to 50 A without rupturing the package — critical for secondary-side protection in power supplies where the available fault current from the downstream bulk capacitor can hit tens of amps during a short. ## Melting I²t and inrush handling The melting I²t is 0.0425 — a figure that governs how the fuse holds up under repetitive inrush pulses. A capacitor-input filter on a 125 V rail charging through this fuse will see a surge that integrates the I²t; if the pulse energy exceeds the fuse's I²t rating, the element ages or opens prematurely. For a 375 mA fast-blow, 0.0425 is typical for protecting downstream silicon without nuisance clearing on moderate inrush. ## Package, mounting, and temperature range Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the 0451.375NR mounts on the board surface — no through-hole leads. ## Approvals and compliance The 0451.375NR carries CSA and UL approval agency marks — these certify the fuse meets North American safety standards for overcurrent protection. No RoHS or REACH compliance statement appears in the record; verify the date code against the current exemption list if your BOM requires it.","metaTitle":"0451.375NR Littelfuse NANO² 451, 375mA, 125V, Fast-Blow","metaDescription":"Littelfuse 0451.375NR NANO² 451 fast-blow surface-mount fuse, 375mA, 125V AC/DC, 50A breaking capacity. Obsolete — sourced to order against RFQ.","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":"0.0425","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":"0.61 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"375 mA","Operating Temperature":"-55°C~125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.4757","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the melting I²t of 0451.375NR?","answer":"The melting I²t is 0.0425. This value determines how the fuse handles inrush current pulses without nuisance opening or premature aging."},{"question":"What approvals does 0451.375NR carry?","answer":"The fuse is approved by CSA and UL, certifying compliance with North American safety standards for overcurrent protection."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451.375NR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451.375NR 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}}