{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0451.200MRSN","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0451.200MRSN","canonicalUrl":"https://icboms.com/littelfuse-inc/0451.200MRSN","factsUrl":"https://icboms.com/api/mcp/products/0451.200MRSN","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse NANO²® 451 series, SMD fast-blow fuse, 200 mA, 125 VAC, 50 A breaking capacity, 2-SMD square end block package, Tape & Reel.","salesMarkdown":"## 200 mA fast-blow SMD fuse for secondary-side protection The 0451.200MRSN is a Littelfuse NANO²® 451 series surface-mount fuse rated 200 mA at 125 VAC, with a 50 A interrupting capacity at rated voltage. Fast-blow response time means it clears quickly on moderate overcurrents — suited for protecting semiconductor circuits where the fault energy must be limited before the junction overheats. ## Breaking capacity and cold resistance Breaking capacity of 50 A at 125 VAC covers most secondary-side fault scenarios in control and instrumentation supplies — the fuse can interrupt a short-circuit current up to that level without rupturing. DC cold resistance is 0.8372 Ohms, which at 200 mA produces about 33 mW of self-heating — negligible for the 2-SMD square end block package in still air. Melting I²t of 0.0089 A²s gives a fast energy let-through; useful when the downstream silicon's surge rating is tight. ## Temperature range and approvals Approved by CSA and UR (UL Recognized) — accepted in North American and Canadian equipment listings without additional agency testing.","metaTitle":"0451.200MRSN Littelfuse NANO² 451, 200 mA, 125 VAC","metaDescription":"0451.200MRSN Littelfuse NANO² 451 SMD fuse, 200 mA, 125 VAC, 50 A breaking capacity, fast blow, -55 to 125°C. Active, sourced 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)","Fuse Type":"Board Mount (Cartridge Style Excluded)","Melting I²t":"0.0089","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":"0.8372 Ohms","Voltage Rating - AC":"125 V","Current Rating (Amps)":"200 mA","Operating Temperature":"-55°C~125°C","Breaking Capacity @ Rated Voltage":"50A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.4469","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/604a0e4c498aa97d2607992508357d04.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/0451.200MRSN/alternatives.json"},"ai":{"faq":[{"question":"What is the closest pin-compatible alternative to 0451.200MRSN in the NANO² 451 series?","answer":"The NANO² 451 series includes multiple current ratings in the same 2-SMD square end block package."},{"question":"What compliance documentation does Littelfuse provide for 0451.200MRSN?","answer":"The fuse carries CSA and UR (UL Recognized) approvals. RoHS and REACH compliance documentation is typically available from Littelfuse upon request; no specific cert numbers are listed in the spec record."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0451.200MRSN","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0451.200MRSN 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}}