{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"ULN2801A","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"ULN2801A","canonicalUrl":"https://icboms.com/stmicroelectronics/ULN2801A","factsUrl":"https://icboms.com/api/mcp/products/ULN2801A","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics ULN2801A, 8 NPN Darlington transistor array, 50V Vce, 500mA per channel, 2.25W max, 18-DIP through-hole package, Tube.","salesMarkdown":"## Active BOM line — no last-time-buy pressure The ULN2801A: ROHS3 compliance is confirmed, so the part clears EU material declarations without exemption paperwork. The ULN2801A packs eight NPN Darlington pairs in a single 18-pin DIP, each rated for 500 mA continuous collector current and a 50 V collector-emitter breakdown. That is enough to drive a bank of 24 VDC relays, small solenoids, or indicator lamps from a logic-level signal — the Darlington gain (hFE 1000 minimum at 350 mA) means the microcontroller or PLC output only needs to source about 350 µA per channel to switch the load. The catch: 2.25 W total package dissipation. At 350 mA per channel with a 1.6 V Vce sat, each channel dissipates roughly 0.56 W. Running all eight channels simultaneously at that current would exceed the package limit — the thermal budget forces derating. In practice, most relay-driver applications cycle channels, so the average dissipation stays under the ceiling. ## Through-hole 18-DIP — field-swappable without a hot-air station The 18-DIP (0.300-inch row spacing) through-hole package is the socket-friendly form factor. No hot-air rework station needed — a manual solder sucker and iron swap it in minutes on a customer site. For a control cabinet or conveyor-side panel, the temperature margin is fine. ## Sourcing and second-source reality The closest functional second-source is the ULN2803A, which is pin-compatible and shares the same package, power dissipation, and per-channel ratings. The difference is the input resistor value — the ULN2803A has a higher-value base resistor, making it a direct match for 5 V logic, while the ULN2801A is optimized for a slightly different input threshold. In most relay-driver sockets, they swap without a board change.","metaTitle":"STMicroelectronics ULN2801A 8 NPN Darlington Array, 500mA","metaDescription":"Active STMicroelectronics ULN2801A 8 NPN Darlington transistor array. 50V Vce, 500mA per channel, 2.25W max. 18-DIP through-hole. ROHS3 compliant.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Analog & Data Acquisition"],"specifications":{"Package":"Tube","Power - Max":"2.25W","Mounting Type":"Through Hole","Package / Case":"18-DIP (0.300\\\", 7.62mm)","Transistor Type":"8 NPN Darlington","lifecycle_stage":"eol_hot","Operating Temperature":"-20°C ~ 150°C (TJ)","Supplier Device Package":"18-DIP","Vce Saturation (Max) @ Ib, Ic":"1.6V @ 500µA, 350mA","Current - Collector (Ic) (Max)":"500mA","DC Current Gain (hFE) (Min) @ Ic, Vce":"1000 @ 350mA, 2V","Voltage - Collector Emitter Breakdown (Max)":"50V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$2.79","priceTiers":[{"qty":1,"price":"$2.79000","currency":"USD"},{"qty":20,"price":"$2.50500","currency":"USD"},{"qty":40,"price":"$2.36325","currency":"USD"},{"qty":100,"price":"$2.01340","currency":"USD"},{"qty":260,"price":"$1.89054","currency":"USD"},{"qty":500,"price":"$1.65422","currency":"USD"},{"qty":1000,"price":"$1.37064","currency":"USD"},{"qty":2500,"price":"$1.27611","currency":"USD"},{"qty":5000,"price":"$1.22885","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/d45d0fb16f9f0d1f4ccb53c7b5e84fce.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/ULN2801A/alternatives.json"},"ai":{"faq":[{"question":"Will ULN2801A drop into a panel that was specified around ULN2803A without rewiring?","answer":"Yes, the ULN2801A and ULN2803A are pin-compatible in the same 18-DIP package. The main difference is the input resistor value — the ULN2801A has a lower base resistance, so it may trigger at a slightly lower input voltage. For a 5 V logic interface, the ULN2803A is the more common choice, but the ULN2801A will physically fit and function in the same socket without rewiring."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/ULN2801A","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/ULN2801A 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}}