{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451.080MRSN","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451.080MRSN","canonicalUrl":"https://icboms.com/littelfuse-inc/0451.080MRSN","factsUrl":"https://icboms.com/api/mcp/products/0451.080MRSN","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse Inc. NANO²® 451 series, Board Mount Surface Mount Fuse, Fast Blow, 80 mA, 125 VAC, 50 A breaking capacity, 2-SMD Square End Block package, Tape & Reel.","salesMarkdown":"## 80 mA fast-blow for secondary-side protection The Littelfuse 0451.080MRSN is an 80 mA fast-blow surface-mount fuse from the NANO²® 451 series, designed to clear overcurrent faults on densely populated boards where a through-hole pigtail fuse won't fit the layout. Rated 125 VAC with a 50 A interrupting capacity, it safely opens a fault up to that level without arcing across the element or damaging the surrounding traces — the 50 A ceiling is the maximum fault current the fuse can interrupt at its rated voltage. ## Melting I²t and cold resistance — the coordination numbers The melting I²t of 0.00033 A²s is the energy required to vaporise the fuse element — this is the number you compare against the I²t rating of the downstream semiconductor (diode, regulator, or IC input) to guarantee the fuse opens before the part fails short. Cold resistance of 4.05 Ohms means the fuse adds about 0.32 V drop at rated current — negligible on a 5 V rail but worth accounting for in a 1.8 V supply where every millivolt of IR drop eats into the load's headroom. ## Industrial temperature range and approvals Carries CSA and UR approval marks — accepted in North American and Canadian equipment without a separate component-level safety evaluation, which saves a qualification cycle on the bill of materials.","metaTitle":"Littelfuse 0451.080MRSN NANO² 451 Fuse, 80 mA, 125 VAC","metaDescription":"Littelfuse 0451.080MRSN NANO² 451 surface-mount fast-blow fuse, 80 mA at 125 VAC, 50 A breaking capacity. Active lifecycle, CSA/UR approved. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Protection"],"specifications":{"Mfr":"Littelfuse Inc.","Color":"-","Series":"NANO²® 451","Package":"Tape & Reel (TR)","Fuse Type":"Board Mount (Cartridge Style Excluded)","Melting I²t":"0.00033","Mounting Type":"Surface Mount","Response Time":"Fast Blow","Package / Case":"2-SMD, Square End Block","Product Status":"Active","Approval Agency":"CSA, UR","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":"4.05 Ohms","Voltage Rating - AC":"125 V","Current Rating (Amps)":"80 mA","Operating Temperature":"-55°C ~ 125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.1545","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/0451.080MRSN/alternatives.json"},"ai":{"faq":[{"question":"What is the 0451.080MRSN's breaking capacity at 125 VAC?","answer":"The 0451.080MRSN has a breaking capacity of 50 A at its rated voltage of 125 VAC — this is the maximum fault current the fuse can safely interrupt without rupturing or sustaining an arc."},{"question":"What approvals does the 0451.080MRSN carry?","answer":"The 0451.080MRSN carries CSA and UR approvals, meaning it is accepted for use in North American and Canadian equipment without requiring a separate component-level safety evaluation."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451.080MRSN","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451.080MRSN when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:49:49.435Z","lastPublished":"2026-08-11T15:49:49.435Z","indexable":true}}