{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"T635T-8T","brand":"STMicroelectronics","brandSlug":"stmicroelectronics","productSlug":"T635T-8T","canonicalUrl":"https://icboms.com/stmicroelectronics/T635T-8T","factsUrl":"https://icboms.com/api/mcp/products/T635T-8T","rawCanonicalId":null},"summary":{"shortDescription":"STMicroelectronics Snubberless™ series, T635T-8T, Alternistor - Snubberless TRIAC, Single, Through Hole, TO-220-3, 800 V off-state, 6 A RMS, -40°C to 150°C junction temperature.","salesMarkdown":"## 800 V Alternistor for inductive loads — no snubber needed The STMicroelectronics T635T-8T is a 6 A RMS Alternistor TRIAC from the Snubberless™ series, rated for 800 V off-state voltage and housed in a TO-220 through-hole package. It is designed for AC load switching in industrial and appliance environments where inductive kickback would otherwise demand an external RC snubber — the Snubberless™ construction handles the dv/dt transient internally. Typical applications include motor speed controllers, heating-element drivers, solid-state relays, and lighting ballasts where the 150°C junction temperature rating provides margin for thermally constrained enclosures. ## Gate drive and triggering The T635T-8T triggers with a maximum gate current of 35 mA and a maximum gate voltage of 1.3 V. A holding current of 40 mA ensures the device latches once triggered, so the gate drive can be removed after the half-cycle. For designs using a microcontroller or optocoupler output, confirm the driver can source 35 mA peak into the gate — many logic-level couplers need a buffer transistor at this level. Through-hole TO-220-3 package with a standard TO-220AB footprint. The tab is electrically common with the center pin (MT2), so heatsink mounting requires an insulating washer and thermal compound if the heatsink is grounded. No end-of-life notices or last-time-buy windows are on record.","metaTitle":"STMicroelectronics T635T-8T Snubberless TRIAC, 800V, 6A","metaDescription":"ST T635T-8T Alternistor TRIAC, 800V off-state, 6A RMS, Snubberless™, TO-220, -40 to 150°C. Active, ROHS3.","metaKeywords":null},"attributes":{"series":"Snubberless™","packageCase":null,"mountingType":null,"rohsStatus":"ROHS3 Compliant","productStatus":"Active","categoryPath":["Discrete Semiconductors"],"specifications":{"Mfr":"STMicroelectronics","Series":"Snubberless™","Package":"Tube","Triac Type":"Alternistor - Snubberless","Configuration":"Single","Mounting Type":"Through Hole","Package / Case":"TO-220-3","Product Status":"Active","lifecycle_stage":"eol_hot","Base Product Number":"T635","Voltage - Off State":"800 V","Operating Temperature":"-40°C~150°C(TJ)","Supplier Device Package":"TO-220","Current - Hold (Ih) (Max)":"40 mA","Current - Gate Trigger (Igt) (Max)":"35 mA","Voltage - Gate Trigger (Vgt) (Max)":"1.3 V","Current - On State (It (RMS)) (Max)":"6 A","Current - Non Rep. Surge 50, 60Hz (Itsm)":"45A, 47A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.4400","priceTiers":[{"qty":1,"price":"$1.44000","currency":"USD"},{"qty":10,"price":"$1.28300","currency":"USD"},{"qty":100,"price":"$1.00030","currency":"USD"},{"qty":500,"price":"$0.82634","currency":"USD"},{"qty":1000,"price":"$0.71802","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/9366021f3420039cd94608a43002e463.pdf","sourceUrl":null,"alternativesUrl":"https://icboms.com/api/mcp/products/T635T-8T/alternatives.json"},"ai":{"faq":[{"question":"What is the lead time for T635T-8T?","answer":"Lead time is confirmed at RFQ; typical supply posture is quoted against current distributor inventory. Submit an RFQ for current lead-time estimates."},{"question":"Is T635T-8T a direct replacement for T635T-6T?","answer":"The T635T-8T has an 800 V off-state voltage rating versus the 600 V rating of the T635T-6T. For a 600 V circuit, the -8T is an over-rated drop-in substitute; for a 230 VAC line both work, but the -8T provides higher voltage margin. Verify the gate trigger and holding current match your drive circuit — both share the same T635 base product number and TO-220 package."},{"question":"Can T635T-8T be used for zero-crossing switching?","answer":"Yes, the T635T-8T can be used in zero-crossing circuits. Because it is an Alternistor (Snubberless™ type), it commutates cleanly at zero current without external snubber components, making it well suited for resistive and inductive loads where zero-crossing turn-off is desired."},{"question":"What is the maximum junction temperature for T635T-8T?","answer":"The maximum junction temperature is 150°C. This allows operation in high-ambient enclosures or with limited heatsinking, provided the RMS current is derated per the thermal impedance curve."},{"question":"What is a Snubberless TRIAC?","answer":"A Snubberless TRIAC is designed to switch inductive loads without an external RC snubber network. The T635T-8T achieves this through an Alternistor structure that improves dv/dt immunity and commutates cleanly at current zero, reducing BOM count and board area in motor and transformer applications."},{"question":"What is the difference between a TRIAC and an Alternistor?","answer":"An Alternistor is a subtype of TRIAC designed for higher dv/dt immunity and better commutation on inductive loads. The T635T-8T is an Alternistor - Snubberless type, meaning it can handle the reverse voltage spike from inductive turn-off without the external snubber that a standard TRIAC would require."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/stmicroelectronics/T635T-8T","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/stmicroelectronics/T635T-8T when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:49:49.435Z","lastPublished":"2026-08-11T15:49:49.435Z","indexable":true}}