{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"STD815CP40","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"STD815CP40","canonicalUrl":"https://icboms.com/stmicroelectronics/STD815CP40","factsUrl":"https://icboms.com/api/mcp/products/STD815CP40","rawCanonicalId":null},"summary":{"shortDescription":"ST STD815CP40 complementary NPN/PNP Darlington transistor pair, 400V VCEO, 1.5A Ic, 2.6W max, 8-DIP through-hole package.","salesMarkdown":"## 400 V VCEO — the flyback and offline driver fit The STD815CP40 is a complementary NPN/PNP Darlington transistor pair in a single 8-DIP package, designed for medium-voltage, medium-current switching. Its 400 V collector-emitter breakdown (VCEO) and 1.5 A continuous collector current cover the primary-side switch in low-power flyback converters, relay and solenoid drivers in 240 VAC industrial controls, and CFL or LED ballast circuits. The 2.6 W power dissipation ceiling in the 8-DIP through-hole package means you need to consider heatsinking or derating above ~500 mA continuous — the SOA is real-world limited by the package, not the silicon. ## Vce(sat) and hFE — the drive margin check Vce(sat) is specified at 1 V max with 50 mA base drive into 350 mA collector current. That 16 minimum hFE at 350 mA / 5 V is low — typical Darlington territory — so the base drive needs to be sized for worst-case gain. A microcontroller GPIO will not drive it directly; you need a pre-driver transistor or a resistor from a higher-voltage rail. The 1 mA max collector cutoff at rated VCEO matters in lightly loaded offline circuits where leakage can pull a gate or relay false. ## Obsolete — sourcing via independent distribution Official production has ended; there is no last-time-buy window remaining. Availability is through independent distribution and surplus channels only. Every unit we supply is sourced from vetted inventory with traceable date-code and marking consistency — the laser etch is a fingerprint, and we decap-sample lots where the marking looks off. If you need a drop-in through-hole replacement, the complementary pair in an 8-DIP is uncommon; a surface-mount migration to discrete NPN/PNP Darlingtons in SOT-223 or DPAK is the practical path for new designs.","metaTitle":"STD815CP40 NPN/PNP Transistor, 400V 1.5A 8-DIP","metaDescription":"STD815CP40 complementary NPN/PNP transistor pair. 400V VCEO, 1.5A Ic, 2.6W max, 8-DIP. RFQ for price and availability.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Obsolete","categoryPath":["Discrete Semiconductors"],"specifications":{"Mfr":"STMicroelectronics","Series":"-","Package":"Tube","Power - Max":"2.6W","Mounting Type":"Through Hole","Package / Case":"8-DIP (0.300\\\", 7.62mm)","Product Status":"Obsolete","Transistor Type":"NPN, PNP","lifecycle_stage":"eol_hot","Base Product Number":"STD815","Operating Temperature":"-","Frequency - Transition":"-","Supplier Device Package":"8-DIP","Vce Saturation (Max) @ Ib, Ic":"1V @ 50mA, 350mA","Current - Collector (Ic) (Max)":"1.5A","Current - Collector Cutoff (Max)":"1mA","DC Current Gain (hFE) (Min) @ Ic, Vce":"16 @ 350mA, 5V","Voltage - Collector Emitter Breakdown (Max)":"400V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/b3fedadabd3cd504232285653f1219ef.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/STD815CP40/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy STD815CP40 and how do I get a price?","answer":"Submit an RFQ; we confirm availability and current pricing from vetted inventory at quote time. No stock or price figures are published due to the part's obsolete status."},{"question":"What is the equivalent of STD815CP40?","answer":"There is no direct pin-compatible replacement listed by STMicroelectronics. For a through-hole complementary NPN/PNP Darlington pair at 400 V / 1.5 A, the closest functional equivalents are discrete Darlingtons such as the TIP127 (PNP) and TIP122 (NPN) in TO-220, or the MJE series — these require a two-device layout and different footprint. For new designs, consider surface-mount Darlingtons in SOT-223 or DPAK."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/STD815CP40","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/STD815CP40 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-17T19:50:00.618Z","lastPublished":"2026-07-17T19:50:00.618Z","indexable":true}}