{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"ULN2068B","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"ULN2068B","canonicalUrl":"https://icboms.com/stmicroelectronics/ULN2068B","factsUrl":"https://icboms.com/api/mcp/products/ULN2068B","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics ULN2068B, Quad NPN Darlington array, 50 V Vceo, 1.75 A Ic per channel, 1.4 V Vce(sat) at 2 mA Ib, 1.25 A Ic, 16-PowerDIP through-hole package, -20°C to 85°C operating temperature.","salesMarkdown":"## Quad Darlington array for medium-current switched loads The STMicroelectronics ULN2068B integrates four NPN Darlington pairs in a single 16-PowerDIP through-hole package, each rated for a continuous collector current of 1.75 A and a collector-emitter breakdown voltage of 50 V. Each channel includes the base resistor and a clamp diode for inductive flyback, so a relay, solenoid, or stepper-motor winding connects directly between the output and the supply rail without an external catch diode. The 1.4 V maximum saturation voltage at 1.25 A (2 mA base drive) sets the per-channel conduction loss — at full load that is about 2.2 W total across four channels, which the PowerDIP's leadframe and the PCB copper must sink. ## 1.75 A per channel — where the current rating lands The 1.75 A maximum collector current per Darlington is the absolute ceiling at 25°C case temperature; the practical continuous current in a 85°C ambient, still-air environment is lower because the 1 W package power limit and the junction-to-ambient thermal path through the 16 leads set the real derating. For a 12 V relay bank pulling 500 mA per coil, the ULN2068B runs with 2.8 V of headroom and about 0.7 W total dissipation — well within the thermal budget. For a 24 V solenoid at 1.2 A, the 1.4 V saturation drop leaves 22.6 V across the load and dissipates 1.68 W per channel, which requires airflow or a heatsink on the PowerDIP body. ## Through-hole PowerDIP — board integration note The 16-PowerDIP (0.300-inch row spacing, 7.62 mm body width) is a through-hole package intended for wave-solder assembly or manual insertion in prototype runs. The 20 mm × 7.10 mm body has staggered lead exits that increase the copper cross-section from the die to the PCB pad, improving thermal conduction compared to a standard DIP-16. For best thermal performance, connect all GND pins (pins 9 and 10) to a continuous ground plane with wide traces, and avoid routing sensitive analog signals under the package — the Darlington outputs switch inductive loads and couple switching noise into the substrate. The base product number ULN2068 covers the full family including the A and B suffix variants.","metaTitle":"STMicroelectronics ULN2068B Quad NPN Darlington","metaDescription":"ULN2068B quad NPN Darlington array, 50 V Vceo, 1.75 A Ic per channel, 1.4 V Vce(sat) at 1.25 A. 16-PowerDIP through-hole, -20°C to 85°C.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Discrete Semiconductors"],"specifications":{"Mfr":"STMicroelectronics","Series":"-","Package":"Tube","Power - Max":"1W","Mounting Type":"Through Hole","Package / Case":"16-PowerDIP (0.300\\\", 7.62mm)","Product Status":"Active","Transistor Type":"4 NPN Darlington (Quad)","lifecycle_stage":"eol_hot","Base Product Number":"ULN2068","Operating Temperature":"-20°C~85°C(TA)","Frequency - Transition":"-","Supplier Device Package":"16-PowerDIP (20x7.10)","Vce Saturation (Max) @ Ib, Ic":"1.4V @ 2mA, 1.25A","Current - Collector (Ic) (Max)":"1.75A","Current - Collector Cutoff (Max)":"-","DC Current Gain (hFE) (Min) @ Ic, Vce":"-","Voltage - Collector Emitter Breakdown (Max)":"50V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$6.8000","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/6ef2d88258ab11cb0908a0228224d4e2.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/ULN2068B/alternatives.json"},"ai":{"faq":[{"question":"Is ULN2068B a direct replacement for ULN2003?","answer":"No. The ULN2003 is a 500 mA per-channel Darlington array in a DIP-16 or SO-16 package. The ULN2068B is rated for 1.75 A per channel — 3.5× the current capability — and uses the 16-PowerDIP package with a different leadframe and thermal path. The pinout is the same (1–7 inputs, 8 GND, 9 COM, 10–16 outputs), so it is pin-compatible on the board, but the higher saturation voltage and power dissipation mean the PCB copper and enclosure ventilation must be sized for the ULN2068B's thermal load. For a 500 mA relay bank originally designed around a ULN2003, the ULN2068B will work with no circuit chan"},{"question":"What is the maximum collector current of ULN2068B?","answer":"1.75 A per channel, continuous, at 25°C. The practical limit in a 85°C ambient depends on how many channels are on simultaneously and the PCB's ability to sink the 1 W package power limit. For all four channels conducting 1.75 A each, the total dissipation would exceed 9 W — far above the package rating — so the per-channel current must be derated when multiple outputs are active."},{"question":"Are ULN2068A and ULN2068B interchangeable?","answer":"Yes, they are the same silicon in the same 16-PowerDIP package. The A and B suffixes typically indicate a minor test-limit or temperature-range variation, but both carry the same 1.75 A collector current rating and 50 V breakdown voltage. The ULN2068B is the current-production variant; the ULN2068A may appear in older stock or surplus channels. Confirm the operating temperature range on the specific date code if substituting."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/ULN2068B","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/ULN2068B 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}}