{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"045101.5NR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"045101.5NR","canonicalUrl":"https://icboms.com/littelfuse-inc/045101.5NR","factsUrl":"https://icboms.com/api/mcp/products/045101.5NR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse Inc. NANO²® 451 series, Board Mount (Cartridge Style Excluded) fuse, 045101.5NR, 1.5 A, 125 V AC/DC, Fast Blow, 2-SMD Square End Block package, Tape & Reel.","salesMarkdown":"## 1.5 A fast-blow fuse for secondary-side protection The Littelfuse 045101.5NR is a 1.5 A fast-blow surface-mount fuse from the NANO²® 451 series, rated for 125 V AC and 125 V DC circuits. The fast-blow response means it clears quickly on overcurrent — essential for protecting downstream semiconductors that cannot tolerate sustained fault current. With a breaking capacity of 50 A at the rated voltage, this fuse can safely interrupt fault currents up to that level without rupturing or arcing across the element. The 0.853 melting I²t figure helps coordination engineers size the upstream protection — the fuse element absorbs that energy before opening, so the upstream breaker or fuse sees the clearing event as a downstream fault. ## Obsolete — sourcing through independent channels Littelfuse lists the 045101.5NR as obsolete. No official successor order code is recorded, so the replacement path is not a direct pin-compatible drop-in from the same manufacturer. The part is available through independent surplus and broker channels; quantities and pricing are confirmed at RFQ time against the specific BOM line. For existing designs already qualified on the NANO²® 451 footprint, the 1.5 A rating, fast-blow characteristic, and 2-SMD Square End Block package are the parameters to match when evaluating a functional replacement. The 0.063 Ohm DC cold resistance gives a baseline for voltage drop at rated current — about 95 mV at 1.5 A. ## Regulatory approvals and temperature range The fuse carries CSA, PSE, and UL approvals — covering North American and Japanese regulatory acceptance for equipment-level safety certification.","metaTitle":"Littelfuse 045101.5NR NANO² 451 Fuse, 1.5A Fast Blow, 125V","metaDescription":"Littelfuse 045101.5NR NANO² 451 surface-mount fuse, 1.5A fast-blow, 125V AC/DC, 50A breaking capacity. Obsolete — sourced to order. CSA, PSE, UL approved.","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":"0.853","Mounting Type":"Surface Mount","Response Time":"Fast Blow","Package / Case":"2-SMD, Square End Block","Product Status":"Obsolete","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":"0.063 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"1.5 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/2e33e7b2503f3f5110226be89402b64a.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What approvals does the 045101.5NR carry?","answer":"The fuse is approved by CSA, PSE, and UL. These certifications cover safety compliance for use in equipment sold in North America (CSA, UL) and Japan (PSE)."},{"question":"What is the 045101.5NR used for?","answer":"It is a 1.5 A fast-blow surface-mount fuse for board-level overcurrent protection on 125 V AC or DC circuits. The fast-blow response makes it suitable for protecting sensitive electronics — power supplies, motor drives, or control boards — where a slow-blow fuse would let through too much energy before clearing."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/045101.5NR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/045101.5NR 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}}