{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451003.MRL","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451003.MRL","canonicalUrl":"https://icboms.com/littelfuse-inc/0451003.MRL","factsUrl":"https://icboms.com/api/mcp/products/0451003.MRL","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, 0451003.MRL, board-mount SMD fuse, 3 A, 125 V AC/DC, fast blow, 50 A breaking capacity, 2-SMD square end block package.","salesMarkdown":"## 3 A fast-blow SMD fuse for secondary-side protection The Littelfuse 0451003.MRL is a 3 A fast-blow surface-mount fuse from the NANO²® 451 series, rated for 125 V both AC and DC circuits. Its 50 A breaking capacity at rated voltage means it can safely interrupt a short-circuit fault up to that current without rupturing — critical for clearing a fault on a 125 V rail where the available fault current might hit that level. ## What the ratings mean for your board The 3 A current rating is the continuous current the fuse carries without opening at 25°C ambient. The fast-blow response means it clears quickly on overcurrents — useful for protecting semiconductor circuits that can't tolerate sustained overloads. The 50 A breaking capacity (interrupting rating) at 125 V AC/DC is the maximum fault current the fuse can safely clear; if your power supply's short-circuit output current exceeds 50 A, this fuse may not clear the fault safely, and you'd need a higher-interrupting device. With a melting I²t of 1.65, this fuse tolerates moderate inrush currents without nuisance opening — useful for capacitive input filters or motor start-ups on the secondary side. Surface-mount assembly means it reflows with the board — no hand-soldering required, but also no field-replacement without a soldering iron. ## Approvals and compliance The 0451003.MRL carries CSA, PSE, and UL approvals — accepted in North American, Canadian, and Japanese regulatory jurisdictions.","metaTitle":"Littelfuse 0451003.MRL NANO² 451 SMD Fuse, 3 A, 125 V","metaDescription":"Littelfuse 0451003.MRL NANO² 451 surface-mount fuse, 3 A, 125 V AC/DC, 50 A breaking capacity, fast blow. Active production, sourced per RFQ.","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) Cut Tape (CT)","Fuse Type":"Board Mount (Cartridge Style Excluded)","Melting I²t":"1.65","Mounting Type":"Surface Mount","Response Time":"Fast Blow","Package / Case":"2-SMD, Square End Block","Product Status":"Active","Approval Agency":"CSA, PSE, 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":"0.0227 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"3 A","Operating Temperature":"-55°C ~ 125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.4600","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/2e33e7b2503f3f5110226be89402b64a.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the breaking capacity of 0451003.MRL?","answer":"50 A at the rated 125 V AC or DC. This is the maximum fault current the fuse can safely interrupt — if your circuit's available fault current exceeds 50 A, choose a higher-interrupting fuse."},{"question":"What approvals does the 0451003.MRL carry?","answer":"CSA, PSE, and UL — covering North American, Canadian, and Japanese safety standards."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451003.MRL","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451003.MRL 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}}