{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"045102.5MRL","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"045102.5MRL","canonicalUrl":"https://icboms.com/littelfuse-inc/045102.5MRL","factsUrl":"https://icboms.com/api/mcp/products/045102.5MRL","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse Inc. NANO²® 451 series, Board Mount (Cartridge Style Excluded) surface-mount fuse, 045102.5MRL, 2.5 A, 125 V AC/DC, Fast Blow, 50 A breaking capacity, 2-SMD square end block.","salesMarkdown":"## 2.5 A fast-blow SMD fuse for secondary-side protection The Littelfuse 045102.5MRL is a 2.5 A, 125 V AC/DC fast-blow surface-mount fuse from the NANO²® 451 series, designed to clear quickly on overcurrent events in low-voltage DC rails or secondary AC circuits. With a 50 A interrupting capacity at rated voltage, it handles fault currents typical of secondary-side power supplies and control circuits, though it is not rated for primary distribution-level faults. ## Fast-blow response and let-through energy The fast-blow characteristic with a melting I²t of 1.029 means the fuse opens rapidly on short-circuits, limiting the energy let-through to downstream semiconductors and sensitive loads. A DC cold resistance of 0.0286 Ohms keeps insertion loss low — at 2.5 A the voltage drop is under 72 mV, which matters for low-voltage rails where every millivolt counts. Housed in a 2-SMD square end block measuring 6.10 mm x 2.69 mm x 2.69 mm, the 045102.5MRL fits dense PCB layouts where space is constrained — common in telecom line cards, battery management systems, and portable equipment. ## Temperature grade and approvals CSA, PSE, and UL approvals mean the part is accepted in North American and Asian regulatory jurisdictions without additional qualification testing.","metaTitle":"Littelfuse 045102.5MRL NANO² 451 SMD Fuse, 2.5A, 125V","metaDescription":"Littelfuse 045102.5MRL NANO² 451 surface-mount fast-blow fuse, 2.5 A, 125 V AC/DC, 50 A breaking capacity. Active lifecycle, UL/CSA/PSE approved.","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":"1.029","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":"0.0286 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"2.5 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/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null},"ai":{"faq":[{"question":"How can I order the 045102.5MRL or check availability?","answer":"Submit an RFQ for current availability and pricing; the quote is confirmed against your specific BOM quantity."},{"question":"What approvals does the 045102.5MRL carry?","answer":"The fuse is approved by CSA, PSE, and UL, covering North American and Asian regulatory requirements without additional safety testing."},{"question":"What is the breaking capacity of the 045102.5MRL?","answer":"The 045102.5MRL is rated for 50 A interrupting capacity at 125 V AC/DC, suitable for secondary-side fault clearing in power supplies and control circuits."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/045102.5MRL","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/045102.5MRL 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}}