{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"0603L300SLYR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"0603L300SLYR","canonicalUrl":"https://icboms.com/littelfuse-inc/0603L300SLYR","factsUrl":"https://icboms.com/api/mcp/products/0603L300SLYR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse POLY-FUSE®, LoRho series, PTC resettable fuse, 0603 (1608 Metric) concave package, 3 A hold current, 6 V max, 3 mOhm initial resistance.","salesMarkdown":"## 3 A hold, 6 V max — the LoRho advantage This Littelfuse 0603L300SLYR is a Polymeric PTC resettable fuse from the POLY-FUSE LoRho series, rated for 3 A hold current (Ih) at 6 V max. The LoRho designation means the initial resistance is just 3 mOhms minimum — that is low enough to keep voltage drop negligible in a 3 A power rail, so the fuse does not steal headroom from the load. When a fault pushes current past the 6 A trip threshold, the PTC element heats and latches into a high-resistance state within 5 seconds, limiting the fault to 50 A max. ## What the resistance numbers mean for your rail The 3 mOhm minimum initial resistance (Ri) is the cold-state value. At 3 A continuous, that is only 9 mV drop — irrelevant for a 6 V rail. The 30 mOhm maximum post-trip resistance (R1) is what the PTC settles to after it trips and cools; that is the resistance the circuit sees when the fault is gone but the fuse has not yet been power-cycled to reset. At 85°C the 3 A rating drops to roughly 70% of the 25°C value, so a rail that must hold 3 A at the top of the temperature range needs a higher-rated fuse or active cooling. ## Active production, approvals on file The 0603 concave package (1.60 mm x 0.80 mm footprint, 1.00 mm max thickness) is a standard surface-mount form factor. Tape-and-reel or cut-tape packaging is available, matching standard pick-and-place feeders.","metaTitle":"0603L300SLYR Littelfuse PTC Resettable Fuse, 3A, 6V","metaDescription":"0603L300SLYR Littelfuse POLY-FUSE LoRho PTC resettable fuse, 3A hold, 6V max, 3 mOhm initial resistance, cURus/TUV approved. Active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Circuit Protection"],"specifications":{"Mfr":"Littelfuse Inc.","Type":"Polymeric","Series":"POLY-FUSE®, LoRho","Package":"Tape & Reel (TR); Cut Tape (CT)","Ratings":"-","Lead Spacing":"-","Time to Trip":"5 s","Current - Max":"50 A","Mounting Type":"Surface Mount","Voltage - Max":"6V","Package / Case":"0603 (1608 Metric), Concave","Product Status":"Active","Approval Agency":"cURus, TUV","Thickness (Max)":"0.039\\\" (1.00mm)","lifecycle_stage":"unknown","Size / Dimension":"0.063\\\" L x 0.031\\\" W (1.60mm x 0.80mm)","Current - Trip (It)":"6 A","Height - Seated (Max)":"-","Operating Temperature":"-40°C~85°C","Current - Hold (Ih) (Max)":"3 A","Resistance - Initial (Ri) (Min)":"3 mOhms","Resistance - Post Trip (R1) (Max)":"30 mOhms"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.8500","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/1bba25c221c1a0e464f2c46553bc04f5.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What approvals does the 0603L300SLYR carry?","answer":"The 0603L300SLYR is approved by cURus and TUV, covering North American and European safety standards for polymeric PTC resettable fuses."},{"question":"What is the trip time and max fault current for this PTC?","answer":"The 0603L300SLYR trips within 5 seconds at fault and can interrupt up to 50 A maximum at 6 V."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/0603L300SLYR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/0603L300SLYR 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}}