{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451.750MRSN","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451.750MRSN","canonicalUrl":"https://icboms.com/littelfuse-inc/0451.750MRSN","factsUrl":"https://icboms.com/api/mcp/products/0451.750MRSN","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, 0451.750MRSN surface-mount fast-blow fuse, 750 mA, 125 VAC, 50 A breaking capacity, 2-SMD square end block package, Tape & Reel.","salesMarkdown":"## 750 mA fast-blow in a 2.69 mm square body The 0451.750MRSN is a 750 mA, 125 VAC fast-blow fuse from Littelfuse's NANO²® 451 series. It clears overcurrents quickly, with a 50 A interrupting rating at the rated voltage — enough to handle a hard short on a 125 VAC secondary circuit without the fuse casing rupturing. The 0.185 melting I²t tells you the energy needed to open the element — useful when sizing the fuse against inrush from a capacitive input or a motor start. A downstream DC-DC converter with a 100 µF input cap at 48 V will need a fuse with I²t headroom above the capacitor's charge pulse; this 0.185 figure lets you check that margin before the first prototype. ## Surface-mount footprint and temperature range Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the 0451.750MRSN mounts directly to the PCB — no holder, no through-hole. The ceramic body and silver-plated end caps handle the thermal cycling without fatigue cracking — common in outdoor telecom or engine-bay auxiliary circuits.","metaTitle":"0451.750MRSN Littelfuse NANO² 451 fuse, 750 mA, 125 V","metaDescription":"Littelfuse 0451.750MRSN NANO² 451 surface-mount fuse, 750 mA, 125 VAC, 50 A breaking capacity, fast blow. Active production. Quoted to order.","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":"0.185","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":"0.245 Ohms","Voltage Rating - AC":"125 V","Current Rating (Amps)":"750 mA","Operating Temperature":"-55°C ~ 125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$3.1300","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the breaking capacity of 0451.750MRSN?","answer":"50 A at 125 VAC. This means the fuse can safely interrupt a fault current up to 50 A without arcing or casing rupture — sufficient for secondary-side protection in most AC-DC power supplies."},{"question":"What compliance documentation does Littelfuse provide for 0451.750MRSN?","answer":"The fuse carries CSA and UR (UL Recognized) approvals. RoHS and REACH compliance documentation is available from the manufacturer for this series."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451.750MRSN","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451.750MRSN 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}}