{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3845D8G4","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"UC3845D8G4","canonicalUrl":"https://icboms.com/texas-instruments/UC3845D8G4","factsUrl":"https://icboms.com/api/mcp/products/UC3845D8G4","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments UC3845D8G4 current-mode PWM controller, 48% max duty cycle, up to 500 kHz switching, 12 V to 28 V supply, 8-SOIC package, commercial temperature range.","salesMarkdown":"## What the 48% duty cycle means for your converter The UC3845D8G4 is a current-mode PWM controller from TI's UC3845 family, built for step-up, step-down, and step-up/step-down topologies including boost, buck, buck-boost, flyback, and forward converters. Its 48% maximum duty cycle is the headline limit — it caps the on-time per switching cycle, which directly sets the transformer turns ratio in a flyback or the voltage step-down ratio in a buck. If your design needs more than 48% on-time, this is not the part; step up to the UC3844 (50%) or UC3843 (100%) siblings. ## Switching frequency and supply rails Switching frequency goes up to 500 kHz, which lets you shrink the magnetics and output capacitors compared to a 100 kHz design — good for board-space-constrained supplies. The Vcc range of 12 V to 28 V matches the bias rail from an auxiliary winding or a linear regulator off the bulk DC bus. No clock sync input, so multiple controllers on the same board will beat unless you add external sync circuitry. Fine for benchtop power supplies, office equipment, appliance control boards, and indoor industrial gear. Not for an engine bay, a rooftop telecom enclosure, or a freezer.","metaTitle":"UC3845D8G4 PWM Controller, 48% Duty Cycle, 500 kHz, SOIC-8","metaDescription":"Texas Instruments UC3845D8G4 current-mode PWM controller. 48% max duty cycle, up to 500 kHz switching, 12 V to 28 V supply. Active production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","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":"8-SOIC (0.154\\\", 3.90mm Width)","lifecycle_stage":"eol_hot","Control Features":"Frequency Control","Duty Cycle (Max)":"48%","Number of Outputs":"1","Serial Interfaces":"-","Base Product Number":"UC3845","Output Configuration":"Positive, Isolation Capable","Frequency - Switching":"Up to 500kHz","Operating Temperature":"0°C~70°C(TA)","Synchronous Rectifier":"No","Supplier Device Package":"8-SOIC","Voltage - Supply (Vcc/Vdd)":"12V ~ 28V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/3edad1712993fb3b1751953d793dcfb6.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3845D8G4/alternatives.json"},"ai":{"faq":[{"question":"Does the UC3845D8G4 support 48% duty cycle in both boost and flyback topologies?","answer":"Yes. The 48% maximum duty cycle applies across all supported topologies — boost, buck, buck-boost, flyback, and forward. In a flyback, that 48% cap limits the stored energy per cycle and forces a specific turns ratio; in a boost, it sets the maximum step-up ratio. If you need more than 48%, look at the UC3843 (100%) or UC3844 (50%) variants."},{"question":"What is the recommended equivalent or replacement for the UC3845D8G4?","answer":"No official TI replacement is listed, but the UC3845 family is a standard industry pinout. A generic UC3845D8 in the same SOIC-8 package from another qualified manufacturer is a functional equivalent — same 48% duty cycle, same 500 kHz ceiling, same pin-for-pin footprint. Confirm the operating temperature grade and supply range match your BOM before swapping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/UC3845D8G4","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/UC3845D8G4 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-22T18:03:28.771Z","lastPublished":"2026-07-22T18:03:28.771Z","indexable":true}}