{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"CNY1743S","brand":"onsemi","brandSlug":"onsemi","productSlug":"CNY1743S","canonicalUrl":"https://icboms.com/onsemi/CNY1743S","factsUrl":"https://icboms.com/api/mcp/products/CNY1743S","rawCanonicalId":null},"summary":{"shortDescription":"onsemi CNY174 series optoisolator, 1-channel DC-input phototransistor, 5300Vrms isolation, 160-320% CTR, 70V output, 6-SMD Gull Wing package, Tube.","salesMarkdown":"The CNY1743S is officially marked as Obsolete by onsemi, meaning the manufacturer has ended production and no further last-time-buy windows are open. Sourcing this part now runs through independent distribution — surplus and broker inventory only. Availability and date-code provenance are confirmed at RFQ; no factory lead time applies. ## 5300Vrms isolation — what it means for the BOM The 5300Vrms isolation rating qualifies this optoisolator for reinforced insulation in mains-connected circuits — think AC line monitoring, motor drive feedback, or medical patient-interface isolation where the safety barrier must withstand a 5.3 kV transient without breakdown. The 1 µs rise / 2 µs fall typical switching speed and 2 µs / 3 µs turn-on/off times place it in the general-purpose phototransistor class — adequate for 50/60 Hz line sensing, relay drive, and low-speed logic isolation, but not for high-speed digital buses like I2C or SPI. ## CTR range and drive margin Current transfer ratio spans 160% minimum to 320% maximum at 10 mA forward current — a 2:1 guaranteed spread. This means the LED drive circuit must be designed to the min CTR (160%) to ensure the output saturates reliably, while the max CTR (320%) sets the upper bound on collector current for a given If. Output transistor is rated 70 V Vce max and 50 mA continuous collector current — enough to drive a small relay coil, PLC input, or logic gate directly without a buffer transistor. Supplied in a 6-SMD Gull Wing package (6-SMD, Gull Wing) — the same footprint as the standard DIP-6 through-hole but surface-mount, so it reflows on the board alongside other SMD passives. The supplier device package is 6-SMD. Operating temperature range of -55°C to 100°C covers industrial and military-temperature environments — the opto will function in unheated enclosures, engine bays, or outdoor telecom cabinets without derating.","metaTitle":"onsemi CNY1743S Optoisolator, 5300Vrms, 6-SMD Gull Wing","metaDescription":"onsemi CNY1743S optoisolator, 1-channel DC input, transistor output, 5300Vrms isolation, 160-320% CTR. Obsolete — sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Optoisolators"],"specifications":{"Mfr":"onsemi","Series":"-","Package":"Tube","Input Type":"DC","Output Type":"Transistor with Base","Mounting Type":"Surface Mount","Package / Case":"6-SMD, Gull Wing","Product Status":"Obsolete","lifecycle_stage":"eol_hot","Number of Channels":"1","Base Product Number":"CNY174","Voltage - Isolation":"5300Vrms","Vce Saturation (Max)":"300mV","Operating Temperature":"-55°C~100°C","Rise / Fall Time (Typ)":"1µs, 2µs","Voltage - Output (Max)":"70V","Supplier Device Package":"6-SMD","Current - Output / Channel":"50mA","Current Transfer Ratio (Max)":"320% @ 10mA","Current Transfer Ratio (Min)":"160% @ 10mA","Voltage - Forward (Vf) (Typ)":"1.35V","Turn On / Turn Off Time (Typ)":"2µs, 3µs","Current - DC Forward (If) (Max)":"100 mA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/4a47ea3b51cbb13a83c8d83e21910005.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/CNY1743S/alternatives.json"},"ai":{"faq":[{"question":"What is the closest pin-compatible alternative to CNY1743S in this Optoisolators family?","answer":"The base product number is CNY174, but the specific suffix variant (CNY1743S) is discontinued without a direct drop-in replacement. A board-level redesign using a different optoisolator with matching CTR and isolation may be required."},{"question":"What is CNY1743S's listed input type (DC) on this Optoisolators line?","answer":"Input type is DC — the LED is driven with a DC forward current. Maximum forward current is 100 mA, with a typical forward voltage of 1.35 V."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/onsemi/CNY1743S","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/onsemi/CNY1743S when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-21T06:28:11.739Z","lastPublished":"2026-07-21T06:28:11.739Z","indexable":true}}