{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451001.MRL","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451001.MRL","canonicalUrl":"https://icboms.com/littelfuse-inc/0451001.MRL","factsUrl":"https://icboms.com/api/mcp/products/0451001.MRL","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, Board Mount Surface Mount Fuse, Fast Blow, 1 A, 125 V AC/DC, 50 A Breaking Capacity, 2-SMD Square End Block Package, Tape & Reel.","salesMarkdown":"## 1 A fast-blow fuse for secondary-side protection The Littelfuse 0451001.MRL is a 1 A fast-blow surface-mount fuse from the NANO² 451 series, rated for 125 V AC and DC circuits. The fast-blow response clears quickly on high-fault currents, making it a fit for short-circuit protection rather than slow overload ride-through. Breaking capacity is 50 A at rated voltage — the fuse can safely interrupt a fault up to that level without rupturing or sustaining an arc. Below that threshold, the element opens cleanly; above it, the fuse may not clear and the fault propagates upstream. ## Package and board-fit constraints Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the 0451001.MRL is a surface-mount device intended for automated pick-and-place assembly. The square end-block footprint mates with standard solder pads for this fuse class — no special cutouts or through-hole tooling needed. DC cold resistance is 0.153 ohms, which sets the voltage drop at rated current at roughly 153 mV. ## Temperature range and approvals The fuse does not derate significantly across this band — the melting I²t of 0.459 stays consistent, so coordination with upstream breakers or fuses holds across temperature. Approved by CSA, PSE, and UL — the fuse is accepted in North American and Japanese regulatory jurisdictions without additional agency review. No AEC-Q rating is listed, so it is not formally qualified for automotive stress tests, but the temperature range overlaps with Grade 1 requirements. ## Sourcing and lifecycle posture The NANO² 451 series includes other current ratings in the same package and footprint — a BOM change to a different amp rating requires verifying the I²t coordination and voltage drop, not just the current number.","metaTitle":"Littelfuse 0451001.MRL NANO² 451 Fuse, 1 A Fast Blow, 125 V","metaDescription":"Littelfuse 0451001.MRL NANO² 451 surface-mount fuse, 1 A fast-blow, 125 V AC/DC, 50 A breaking capacity. Active production. CSA/PSE/UL 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":"0.459","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":"0.153 Ohms","Voltage Rating - AC":"125 V","Voltage Rating - DC":"125 V","Current Rating (Amps)":"1 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 compliance documentation does Littelfuse provide for 0451001.MRL?","answer":"The fuse carries CSA, PSE, and UL approvals. RoHS and REACH compliance documentation is typically available from Littelfuse or the distributor upon request — the approvals confirm the fuse meets the safety and material restrictions for those jurisdictions."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451001.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/0451001.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}}