{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3844D","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"UC3844D","canonicalUrl":"https://icboms.com/texas-instruments/UC3844D","factsUrl":"https://icboms.com/api/mcp/products/UC3844D","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments UC3844D, current-mode PWM controller, 48% duty cycle limit, 12 V to 28 V supply, up to 500 kHz switching, 14-SOIC surface-mount package, commercial temperature grade 0°C to 70°C.","salesMarkdown":"## 48% duty-cycle ceiling — the flyback designer's hard stop The UC3844D: It drives a single transistor output and operates from a 12 V to 28 V supply rail, covering the bias range of common offline SMPS designs. The 48% ceiling guarantees the core resets every cycle in a single-ended forward converter. ## Switching frequency and topology reach Switching frequency goes up to 500 kHz. The part supports boost, buck, buck-boost, flyback, and forward topologies, but the 48% duty limit restricts the step-down ratio in a forward converter. No clock sync input and no synchronous rectifier drive — this is a straightforward, low-pin-count controller for cost-sensitive designs, not a multi-phase or high-efficiency synchronous supply. The part is no longer in production, so new builds cannot rely on factory supply. Sourcing is through independent distribution and the open market. We can quote the UC3844D against your BOM quantity — confirm the date-code range and package condition (tube, 14-SOIC) at RFQ time. ## Package and temperature grade — board-fit constraints The UC3844D comes in a 14-SOIC (0.154\", 3.90 mm width) package, surface-mount. If your application sees an engine bay, outdoor telecom cabinet, or motor-drive enclosure, the 0°C lower limit will cause start-up failures below freezing.","metaTitle":"UC3844D PWM Controller 48% Duty Cycle 14-SOIC Obsolete","metaDescription":"Texas Instruments UC3844D current-mode PWM controller, 48% max duty cycle, up to 500 kHz, 14-SOIC. RFQ for current pricing and availability.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Obsolete","categoryPath":["Power Management (PMIC / Gate Driver)"],"specifications":{"Mfr":"Texas Instruments","Series":"-","Package":"Tube","Function":"Step-Up, Step-Down, Step-Up/Step-Down","Topology":"Boost, Buck, Buck-Boost, 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)":"48%","Number of Outputs":"1","Serial Interfaces":"-","Base Product Number":"UC3844","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)":"12V ~ 28V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.6800","priceTiers":[{"qty":1,"price":"$1.62000","currency":"USD"},{"qty":10,"price":"$1.44800","currency":"USD"},{"qty":25,"price":"$1.37400","currency":"USD"},{"qty":100,"price":"$1.12880","currency":"USD"},{"qty":250,"price":"$1.05516","currency":"USD"},{"qty":500,"price":"$0.93248","currency":"USD"},{"qty":1000,"price":"$0.73617","currency":"USD"},{"qty":2500,"price":"$0.69450","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/3edad1712993fb3b1751953d793dcfb6.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3844D/alternatives.json"},"ai":{"faq":[{"question":"What is the maximum duty cycle of UC3844D?","answer":"48%. This is the key selection parameter — it limits the on-time in a single-ended forward converter to guarantee core reset. If your design requires a duty cycle above 48%, the UC3844D will not work."},{"question":"Can UC3844D be used in a flyback converter?","answer":"Yes. The UC3844D supports flyback topology, and the 48% duty cycle is well-suited for discontinuous-mode flyback designs where the duty cycle stays below 50%. The current-mode control provides inherent cycle-by-cycle current limiting, which is a natural fit for flyback converters."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/UC3844D","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/UC3844D when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-17T17:52:20.437Z","lastPublished":"2026-07-17T17:52:20.437Z","indexable":true}}