{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"UC3845BNST","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"UC3845BNST","canonicalUrl":"https://icboms.com/stmicroelectronics/UC3845BNST","factsUrl":"https://icboms.com/api/mcp/products/UC3845BNST","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics UC3845BNST current-mode PWM controller, 8-DIP through-hole, 48% max duty cycle, up to 500 kHz switching, 7.6 V to 30 V supply, boost/flyback topology, transistor driver output.","salesMarkdown":"## 48% duty ceiling — the design constraint that defines this controller The UC3845BNST: Its 48% maximum duty cycle is the hard limit that sets the transformer turns ratio and output voltage range — you cannot push past it for a wider pulse, which means the flyback primary inductance and reflected voltage are locked in at the design stage. Switching frequency runs up to 500 kHz, letting you shrink the magnetic components for a compact supply, though the 48% duty ceiling still governs the on-time budget at any given frequency. ## Through-hole DIP — rework-friendly, socket-ready Housed in an 8-DIP (0.300\", 7.62 mm) through-hole package, this controller is a bench-friendly part. The DIP body survives multiple hot-air cycles without pad lift, and the 0.100-inch pin pitch fits standard sockets or perfboard — no fine-pitch stencil needed. The supply range spans 7.6 V to 30 V on Vcc, which covers direct operation from a rectified 12 V or 24 V rail without an extra regulator. Output is a single transistor driver, positive and isolation-capable, with frequency control on the RT/CT pin. The UC3845N (the standard DIP-8 variant without the ST-specific suffix) is a functional peer within the same family, but verify pin compatibility and any parametric differences against your specific design before substituting.","metaTitle":"UC3845BNST PWM Controller, 48% Duty, 500 kHz, Obsolete","metaDescription":"UC3845BNST current-mode PWM controller. 48% max duty cycle, up to 500 kHz switching, 7.6-30 V supply. 8-DIP through-hole.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Power Management (PMIC / Gate Driver)"],"specifications":{"Mfr":"STMicroelectronics","Series":"-","Package":"Tube","Function":"Step-Up, Step-Up/Step-Down","Topology":"Boost, Flyback","Clock Sync":"No","Output Type":"Transistor Driver","Mounting Type":"Through Hole","Output Phases":"1","Package / Case":"8-DIP (0.300\\\", 7.62mm)","Product Status":"Obsolete","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":"-40°C~150°C(TJ)","Synchronous Rectifier":"No","Supplier Device Package":"8-Mini DIP","Voltage - Supply (Vcc/Vdd)":"7.6V ~ 30V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/143f4d333be649b0dad1d412d3d6d55c.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/UC3845BNST/alternatives.json"},"ai":{"faq":[{"question":"What is the duty cycle of UC3845BNST?","answer":"The maximum duty cycle is 48%. This is a hard limit for the UC3845 variant — it caps the on-time in boost and flyback designs and directly influences transformer turns ratio and output voltage capability."},{"question":"What is the difference between UC3845BNST and UC3845N?","answer":"Both are current-mode PWM controllers from the same UC3845 family with the same 48% max duty cycle and 500 kHz switching ceiling. The UC3845BNST is the STMicroelectronics-specific suffix variant in an 8-DIP package; the UC3845N is the generic industry-standard part. Pin function is identical across the family, but confirm the exact operating temperature range and any minor electrical spec deltas from the respective datasheets before cross-referencing."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/UC3845BNST","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/UC3845BNST 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}}