{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451.315NR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451.315NR","canonicalUrl":"https://icboms.com/littelfuse-inc/0451.315NR","factsUrl":"https://icboms.com/api/mcp/products/0451.315NR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, board mount surface-mount fuse, 0451.315NR, 315 mA, 125 V AC/DC, fast blow, 2-SMD square end block package, Tape & Reel.","salesMarkdown":"## 315 mA fast-blow in a 2-SMD square end block The Littelfuse 0451.315NR is a 315 mA fast-blow surface-mount fuse from the NANO² 451 series, housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm. Rated for 125 V AC and 125 V DC, it provides a breaking capacity of 50 A at the rated voltage — enough to safely interrupt a hard short on a 125 V rail without the fuse casing rupturing. ## What the ratings mean for your board The 0.3918 ohm DC cold resistance means the fuse drops about 124 mV at rated current — negligible in a 125 V circuit, but worth checking if the load is a sensitive analog front-end that sees the voltage drop across the fuse during a transient. Melting I²t of 0.0311 A²s tells you how much energy the fuse absorbs before opening — useful for sizing the fuse to ride through inrush without nuisance trips. A downstream capacitor bank with a higher I²t surge will blow this fuse on power-up. No derating is required within this band, though the fuse's opening time shifts with temperature — it opens faster at 125°C than at 25°C. CSA and cULus approvals are on file, so the part carries the same safety agency marks as when it was in production.","metaTitle":"0451.315NR Littelfuse NANO² 451 Fuse, 315 mA, 125 V","metaDescription":"0451.315NR Littelfuse NANO² 451 surface-mount fuse, 315 mA, 125 V AC/DC, fast blow, 50 A 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":"0.0311","Mounting Type":"Surface Mount","Response Time":"Fast Blow","Package / Case":"2-SMD, Square End Block","Product Status":"Obsolete","Approval Agency":"CSA, cULus","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":"0.3918 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"315 mA","Operating Temperature":"-55°C ~ 125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.5926","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/b741f1b0e0a9e21e6a76cce2b8d96e45.pdf","sourceUrl":null},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451.315NR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451.315NR 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}}