{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3845AD8G4","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"UC3845AD8G4","canonicalUrl":"https://icboms.com/texas-instruments/UC3845AD8G4","factsUrl":"https://icboms.com/api/mcp/products/UC3845AD8G4","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments UC3845AD8G4 current-mode PWM controller, 48% max duty cycle, up to 500 kHz switching frequency, 7.6V to 30V supply, 8-SOIC surface mount package, commercial temperature range.","salesMarkdown":"## Current-mode PWM controller for flyback and boost stages The Texas Instruments UC3845AD8G4 is a current-mode PWM controller for boost, buck, flyback, or forward converters. It delivers a single transistor-driver output with a maximum duty cycle of 48%. The 48% duty cycle ceiling prevents pulse stacking in single-ended flyback converters, keeping the transformer core reset between cycles. ## Switching frequency and transformer sizing The oscillator runs up to 500 kHz, which lets the designer shrink the magnetic components compared to a lower frequency design. There is no clock-sync pin on this variant — the UC3845AD8G4 runs free-running. If synchronisation to an external clock is needed, the UC3845 family does not support it; look at the UCC28C4x series for that feature. ## Supply range and bias design The Vcc range spans 7.6 V to 30 V, covering common bias rails like 12 V and 24 V industrial supplies without a pre-regulator. The undervoltage lockout (UVLO) threshold for the UC3845 variant is 8.4 V (start) / 7.6 V (stop), which matches the lower end of the supply range — the controller starts when Vcc crosses 8.4 V and shuts down if it drops below 7.6 V. It belongs in indoor power supplies, telecom line cards, and benchtop equipment — not in an engine bay, outdoor enclosure, or any location where the ambient temperature cycles below freezing or above 70°C. The tube shipment is fine for prototyping and low-volume production.","metaTitle":"UC3845AD8G4 Current-Mode PWM Controller, 48% Duty Cycle","metaDescription":"Texas Instruments UC3845AD8G4 current-mode PWM controller. 48% max duty cycle, up to 500 kHz switching, 7.6V-30V supply. 8-SOIC, 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, 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)":"7.6V ~ 30V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/167f8b16f2b0abe2748ff562a0463921.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3845AD8G4/alternatives.json"},"ai":{"faq":[{"question":"Can the UC3845AD8G4 be used in a flyback converter?","answer":"Yes, the UC3845AD8G4 is specifically designed for flyback topologies. The 48% maximum duty cycle is the correct clamp for a single-ended flyback — it ensures the transformer core resets fully before the next cycle starts. The current-mode control loop also provides 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/UC3845AD8G4","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/UC3845AD8G4 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}}