{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3842AD8TRG4","brand":"Texas Instruments","brandSlug":"texas-instruments","productSlug":"UC3842AD8TRG4","canonicalUrl":"https://icboms.com/texas-instruments/UC3842AD8TRG4","factsUrl":"https://icboms.com/api/mcp/products/UC3842AD8TRG4","rawCanonicalId":null},"summary":{"shortDescription":"Texas Instruments UC3842AD8TRG4, current-mode PWM controller, up to 500 kHz switching, 96% max duty cycle, 10V to 30V supply, 8-SOIC package.","salesMarkdown":"## Current-mode PWM controller for offline flyback and forward converters The Texas Instruments UC3842AD8TRG4 is a current-mode PWM controller designed for step-up, step-down, and step-up/step-down topologies including boost, buck, flyback, and forward converters. It drives a single transistor output stage at switching frequencies up to 500 kHz, with a maximum duty cycle of 96% — wide enough for offline flyback designs where the input voltage dips below 100 VAC. ## Switching frequency and duty cycle — sizing the transformer and snubber The 500 kHz ceiling lets you shrink the magnetic core in a flyback transformer compared to a 100 kHz design, but the trade-off is higher switching losses in the MOSFET and snubber. The 96% max duty cycle keeps the controller running through low-line conditions — at 85 VAC input a flyback converter still regulates the output without dropping out of cycle-by-cycle current limit. Supply voltage range of 10 V to 30 V on Vcc/Vdd sets the startup resistor value and the UVLO thresholds. At 10 V the controller is fully operational; below that the undervoltage lockout holds the output off, preventing the MOSFET from operating in the linear region during brownout. The tape-and-reel delivery (TR suffix) matches pick-and-place feeders for volume assembly.","metaTitle":"UC3842AD8TRG4 Current-Mode PWM Controller, 500 kHz, 8-SOIC","metaDescription":"Texas Instruments UC3842AD8TRG4 current-mode PWM controller. 96% max duty cycle, up to 500 kHz switching, 10V to 30V 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":"Tape & Reel (TR)","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)":"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":"8-SOIC","Voltage - Supply (Vcc/Vdd)":"10V ~ 30V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.4480","priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/536891bbf6907bbea70f31ce571541e7.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3842AD8TRG4/alternatives.json"},"ai":{"faq":[{"question":"Is UC3842AD8TRG4 obsolete?","answer":"No. There is no end-of-life or last-time-buy notice on file."},{"question":"Can UC3842AD8TRG4 be used in a flyback converter?","answer":"Yes. The UC3842AD8TRG4 is explicitly rated for flyback topology as part of its step-up/step-down capability. The 96% max duty cycle and up to 500 kHz switching frequency are well suited for offline flyback designs."},{"question":"What is the difference between UC3842 and UC3842AD8TRG4?","answer":"The base part UC3842 is the generic current-mode PWM controller; the UC3842AD8TRG4 suffix indicates the specific variant in an 8-SOIC package (AD8) supplied in tape and reel (TR). The functional specifications — up to 500 kHz switching, 96% duty cycle, 10 V to 30 V supply — are identical across the family."},{"question":"What is the equivalent of UC3842AD8TRG4?","answer":"The UC3842AD8TRG4 is a standard current-mode PWM controller. Pin-compatible equivalents from other manufacturers include the KA3842A (Fairchild/ON Semiconductor) and the SG3842 (Microsemi). All share the same 8-pin SOIC pinout and similar UVLO thresholds. Confirm the exact switching frequency and duty cycle limits against your design margins."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/texas-instruments/UC3842AD8TRG4","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/texas-instruments/UC3842AD8TRG4 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}}