{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3842ADTR","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"UC3842ADTR","canonicalUrl":"https://icboms.com/texas-instruments/UC3842ADTR","factsUrl":"https://icboms.com/api/mcp/products/UC3842ADTR","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments UC3842ADTR, current-mode PWM controller, 14-SOIC, 96% max duty cycle, up to 500 kHz switching, 10 V–30 V supply, 0°C–70°C operation.","salesMarkdown":"## What the 96% duty cycle means for your transformer design The UC3842ADTR is a current-mode PWM controller from Texas Instruments that drives a single transistor output at a maximum duty cycle of 96%. That near-unity duty cycle is the headline parameter for flyback and forward converters: it allows the primary switch to stay on for almost the entire switching period, which directly sets the minimum off-time available for transformer core reset. In a forward converter, a 96% duty cycle forces a reset winding or active clamp to complete the reset in the remaining 4% — a design constraint that drives the turns ratio and the clamp voltage stress on the switch. ## Switching frequency ceiling and gate-drive budget The controller oscillates up to 500 kHz. At the upper end of that range, the gate-drive current drawn from the Vcc rail (10 V–30 V,) becomes a significant fraction of the bias supply budget — a 1 nF gate capacitance switched at 500 kHz draws roughly 0.5 mA from the driver, which the UC3842ADTR's totem-pole output can handle, but the designer must account for it in the auxiliary winding regulation. The 500 kHz ceiling also shrinks the transformer core cross-section, which is the usual reason to push frequency higher in a compact supply. ## Temperature grade and commercial deployment boundary That commercial temperature range fits indoor power supplies, office equipment, and appliance PSUs, but it excludes outdoor telecom cabinets, engine-bay converters, and any environment where the ambient can dip below freezing or rise above 70°C. For those applications, the industrial-grade UC3842A (or the automotive AEC-Q100 LM5150QURUMRQ1,) extends the temperature range to -40°C or higher. ## Package and supply rail fit The 10 V–30 V supply range means the controller can be biased directly from a rectified 24 V AC auxiliary winding or a 12 V–15 V regulated rail, but it cannot run from a 5 V-only bias — a 12 V rail is the practical minimum. The single transistor-driver output drives an external MOSFET or BJT; there is no synchronous rectifier output, so the secondary-side rectifier must be a diode or a separate SR controller.","metaTitle":"UC3842ADTR – TI Current-Mode PWM Controller, 14-SOIC, Active","metaDescription":"Texas Instruments UC3842ADTR current-mode PWM controller. 96% max duty cycle, up to 500 kHz switching, 10 V–30 V supply. 14-SOIC, active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Power Management (PMIC / Gate Driver)"],"specifications":{"Mfr":"Texas Instruments","Series":"-","Package":"Tape & Reel (TR); Cut Tape (CT)","Function":"Step-Up, Step-Down, Step-Up/Step-Down","Topology":"Boost, Buck, Flyback, Forward","Clock Sync":"No","Output Type":"Transistor Driver","Mounting Type":"Surface Mount","Output Phases":"1","Package / Case":"14-SOIC (0.154\\\", 3.90mm Width)","Product Status":"Active","lifecycle_stage":"eol_hot","Control Features":"Frequency Control","Duty Cycle (Max)":"96%","Number of Outputs":"1","Serial Interfaces":"-","Base Product Number":"UC3842","Output Configuration":"Positive, Isolation Capable","Frequency - Switching":"Up to 500kHz","Operating Temperature":"0°C~70°C(TA)","Synchronous Rectifier":"No","Supplier Device Package":"14-SOIC","Voltage - Supply (Vcc/Vdd)":"10V ~ 30V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.1200","priceTiers":[{"qty":1,"price":"$1.12000","currency":"USD"},{"qty":10,"price":"$1.00100","currency":"USD"},{"qty":25,"price":"$0.94960","currency":"USD"},{"qty":100,"price":"$0.78020","currency":"USD"},{"qty":250,"price":"$0.72928","currency":"USD"},{"qty":500,"price":"$0.64448","currency":"USD"},{"qty":1000,"price":"$0.50880","currency":"USD"},{"qty":2500,"price":"$0.48000","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/536891bbf6907bbea70f31ce571541e7.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3842ADTR/alternatives.json"},"ai":{"faq":[{"question":"What is the difference between UC3842ADTR and UC3843?","answer":"The primary difference is the undervoltage lockout (UVLO) thresholds. The UC3842ADTR has a UVLO turn-on threshold of 16 V and turn-off of 10 V, while the UC3843 turns on at 8.4 V and off at 7.6 V. That makes the UC3843 suitable for 12 V bias rails and the UC3842ADTR better for 24 V or higher rails. Both share the same pinout, 96% max duty cycle, and up to 500 kHz switching."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/UC3842ADTR","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/UC3842ADTR 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}}