{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"DB4","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"DB4","canonicalUrl":"https://icboms.com/stmicroelectronics/DB4","factsUrl":"https://icboms.com/api/mcp/products/DB4","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics DB4 DIAC, 35-45V breakover voltage, 50 µA breakover current, 2 A peak output, DO-35 axial package, -40°C to 125°C junction temperature.","salesMarkdown":"The DB4 is a bilateral trigger diode (DIAC) from STMicroelectronics, designed to switch on when the voltage across it reaches the breakover threshold of 35 to 45 V. Once triggered, it conducts a peak output current of 2 A — enough to drive the gate of a medium-power TRIAC in phase-control circuits like dimmers, motor speed controllers, and heater regulators. The 50 µA breakover current is the minimum current needed to initiate conduction; below that level the DIAC remains in its high-impedance blocking state. This low trigger current means the RC timing network in a typical phase-control circuit can use smaller capacitors and higher-value resistors, reducing component size and cost. ## Package and temperature — fitting the board and the environment Housed in a DO-35 axial-lead glass package, the DB4 is a through-hole part that mounts directly into a PCB or can be soldered point-to-point. The glass body provides hermetic sealing, making it suitable for humid or condensing environments where plastic-packaged parts might absorb moisture.","metaTitle":"STMicroelectronics DB4 DIAC, 35-45V Breakover, 2A Peak","metaDescription":"ST DB4 DIAC: 35-45V breakover voltage, 2A peak output, DO-35 axial package. Active production, ROHS3 compliant.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Discrete Semiconductors"],"specifications":{"Mfr":"STMicroelectronics","Series":"-","Package":"Tape & Reel (TR); Cut Tape (CT)","Package / Case":"DO-204AH, DO-35, Axial","Product Status":"Active","lifecycle_stage":"eol_hot","Base Product Number":"DB4","Current - Breakover":"50 µA","Voltage - Breakover":"35 ~ 45V","Current - Peak Output":"2 A","Operating Temperature":"-40°C~125°C(TJ)","Supplier Device Package":"DO-35"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.1618","stockQuantity":0,"priceTiers":[{"qty":1,"price":"$0.43000","currency":"USD"},{"qty":10,"price":"$0.36800","currency":"USD"},{"qty":100,"price":"$0.27440","currency":"USD"},{"qty":500,"price":"$0.21562","currency":"USD"},{"qty":1000,"price":"$0.16661","currency":"USD"},{"qty":2000,"price":"$0.16181","currency":"USD"},{"qty":5000,"price":"$0.16180","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/923b50f53238b3ee821252044c86f02f.pdf","sourceUrl":null},"ai":{"faq":[{"question":"Does the DB4 diac come in a DO-35 package?","answer":"Yes, the DB4 is supplied in a DO-35 axial-lead glass package (DO-204AH variant)."},{"question":"What is a DIAC?","answer":"A DIAC (diode for alternating current) is a bilateral trigger device that conducts only when the applied voltage exceeds its breakover threshold. It is commonly used to trigger TRIACs in phase-control circuits."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/DB4","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/DB4 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-07-16T16:20:02.177Z","lastPublished":"2026-07-16T16:20:02.177Z","indexable":true}}