{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"IRF431","brand":"Infineon Technologies","brandSlug":"infineon","productSlug":"IRF431","canonicalUrl":"https://icboms.com/infineon/IRF431","factsUrl":"https://icboms.com/api/mcp/products/IRF431","rawCanonicalId":null},"summary":{"shortDescription":"IRF431, N-Channel MOSFET, 450 V Vds, 4.5 A Id, 1.5 Ohm Rds(on) @ 2.5 A, 10 V, TO-3 through-hole package, -55°C to 150°C Tj.","salesMarkdown":"## 450 V, 4.5 A N-channel — sizing the TO-3 for the job The IRF431 is an N-channel power MOSFET in a TO-3 through-hole package, rated for 450 V drain-source and 4.5 A continuous drain current. That 450 V ceiling puts it squarely in offline power-conversion territory — flyback converters, PFC stages, and high-voltage DC-DC supplies in industrial gear. The TO-3 case is a two-screw mount with a steel cap; you need a mica insulator and thermal grease if the heatsink is grounded, and the tab is the drain, so the mounting hardware must not short to chassis. ## Rds(on) and gate drive — the thermal budget On-resistance is 1.5 Ohm maximum at 2.5 A drain current with 10 V on the gate. That is not a low-Rds(on) part — at 4.5 A the conduction loss hits 30 W, so the TO-3 flange must be bolted to a heatsink sized for that dissipation. Gate threshold is 4 V at 250 µA, but to fully enhance the channel you need the full 10 V drive; a 5 V logic-level gate driver will leave it in the linear region and cook the die. Total gate charge is 30 nC at 10 V, which is modest — a standard gate-driver IC or even a discrete totem-pole can switch it at tens of kHz without excessive drive loss. ## Junction temperature and field survival The practical limit in a repair scenario is the case-to-ambient thermal resistance — the TO-3 package relies on the metal flange to sink heat. If the original heatsink is corroded or the thermal compound dried out, the junction will hit 150°C well below 4.5 A. In a field swap, clean the mounting surface and apply fresh grease; the two 4-40 screws need 6-8 in-lb torque — no more, or you crack the ceramic foot. ## Sourcing — still active, no LTB pressure For a legacy repair, you are not forced into the surplus market yet, though the TO-3 package is less common in new consumer gear. Sourced to order against your BOM quantity; current pricing and lead time confirmed at quote time.","metaTitle":"IRF431 MOSFET, N-Channel 450V 4.5A TO-3, Active","metaDescription":"IRF431 N-Channel MOSFET, 450V Vds, 4.5A Id, 1.5 Ohm Rds(on) at 10V. TO-3 through-hole package. Active lifecycle.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Discrete Semiconductors"],"specifications":{"Vgs":"±20 V","power_w":"75.0","Fet Type":"N-Channel","package_type":"Bulk","mounting_type":"Through Hole","capacitance_uf":"0.0008","product_status":"Active","lifecycle_stage":"eol_hot","supply_voltage_v":"450.0","Vgs(Th) (Max) @ Id":"4 V @ 250µA","switching_current_a":"4.5","Rds On (Max) @ Id, Vgs":"1.5Ohm @ 2.5 A, 10 V","Operating Temperature High":"-55°C to 150°C(TJ)","Gate Charge (Qg) (Max) @ Vgs":"30 nC @ 10 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$1.15","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.icboms.com/de38f4591b69973f791b94ed5c8597db.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is the Rds(on) and maximum drain current of IRF431?","answer":"Maximum on-resistance is 1.5 Ohm at 2.5 A drain current with 10 V gate drive. Continuous drain current is rated at 4.5 A. Both figures are at 25°C case temperature — derate for higher ambient and junction temperature."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/infineon/IRF431","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/infineon/IRF431 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}}