{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"1206L400SLWR","brand":"Littelfuse Inc.","brandSlug":"littelfuse-inc","productSlug":"1206L400SLWR","canonicalUrl":"https://icboms.com/littelfuse-inc/1206L400SLWR","factsUrl":"https://icboms.com/api/mcp/products/1206L400SLWR","rawCanonicalId":null},"summary":{"shortDescription":"Littelfuse Inc. POLY-FUSE®, LoRho series PTC resettable fuse, Type Polymeric, 1206 (3216 Metric) Concave package, 4 A hold current, 6 V max, 2 s time to trip.","salesMarkdown":"## 4 A hold, 8 A trip — the PTC that clears fast and stays low-resistance The Littelfuse 1206L400SLWR is a polymeric PTC resettable fuse from the POLY-FUSE LoRho series, in a 1206 (3216 Metric) concave surface-mount package. It holds 4 A continuously and trips at 8 A, with a maximum interrupt rating of 50 A at 6 V. The LoRho designation means initial resistance is held to 1 mOhm minimum, with post-trip resistance capped at 14 mOhm — this keeps I²R losses negligible in the steady state and lets the PTC sit in a high-current rail without wasting thermal budget. ## Time-to-trip and thermal response At 8 A trip current the device clears in 2 seconds typical — fast enough to protect a 6 V rail feeding a USB port or a battery pack against a dead short, without nuisance tripping on inrush. Derate the hold current above 25°C per the manufacturer's curve — at 85°C ambient the 4 A hold figure drops to roughly 2.5 A. ## Package and board-fit 1206 (3216 Metric) concave package, 3.25 mm x 1.65 mm body, 1.40 mm max thickness. The concave termination profile means the solder fillet wets the end cap on the bottom side — no tombstoning risk during reflow if the pad geometry matches the recommended land pattern. The low profile suits tight board stacks where a radial-lead PTC would interfere with the enclosure lid. ## Approvals and compliance cURus and TUV approved — the part carries the major North American and European safety marks for overcurrent protection components. This simplifies the certification review for the end product.","metaTitle":"Littelfuse 1206L400SLWR PTC Resettable Fuse, 4A Hold, 6V","metaDescription":"Littelfuse 1206L400SLWR POLY-FUSE LoRho PTC resettable fuse, 4A hold current, 6V max, 1206 package. Active production, sourced to order. cURus, TUV approved.","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":"2 s","Current - Max":"50 A","Mounting Type":"Surface Mount","Voltage - Max":"6V","Package / Case":"1206 (3216 Metric), Concave","Product Status":"Active","Approval Agency":"cURus, TUV","Thickness (Max)":"0.055\\\" (1.40mm)","lifecycle_stage":"unknown","Size / Dimension":"0.128\\\" L x 0.065\\\" W (3.25mm x 1.65mm)","Current - Trip (It)":"8 A","Height - Seated (Max)":"-","Operating Temperature":"-40°C ~ 85°C","Current - Hold (Ih) (Max)":"4 A","Resistance - Initial (Ri) (Min)":"1 mOhms","Resistance - Post Trip (R1) (Max)":"14 mOhms"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.1900","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/1bba25c221c1a0e464f2c46553bc04f5.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the hold current and trip current for 1206L400SLWR?","answer":"The hold current (Ih) is 4 A maximum, and the trip current (It) is 8 A. At 8 A the device trips in 2 seconds typical."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/littelfuse-inc/1206L400SLWR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/littelfuse-inc/1206L400SLWR 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}}