{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"BUJ103AX,127","brand":"NXP Semiconductors","brandSlug":"nxp","productSlug":"BUJ103AX127","canonicalUrl":"https://icboms.com/nxp/BUJ103AX127","factsUrl":"https://icboms.com/api/mcp/products/BUJ103AX%2C127","rawCanonicalId":null},"summary":{"shortDescription":"Ween Semiconductors BUJ103AX,127 NPN power bipolar transistor, 400 V Vceo, 4 A Ic, 26 W max power, TO-220-3 Full Pack isolated tab, through-hole mount, 150°C junction temperature.","salesMarkdown":"The Ween Semiconductors BUJ103AX,127 is an NPN power bipolar junction transistor rated for 400 V collector-emitter breakdown and 4 A continuous collector current, housed in a TO-220-3 Full Pack with an isolated tab. The full-pack (TO-220F) package eliminates the need for an insulating washer between the device and the heatsink, simplifying assembly and improving thermal transfer in designs where the heatsink is chassis-grounded. ## Can BUJ103AX handle 400 V in a switching circuit? The 400 V Vceo rating is the collector-emitter breakdown voltage at zero base drive — it defines the maximum voltage the transistor can block when off. In a typical flyback or forward converter running off a 240 V AC rectified bus (≈340 V DC), this part provides adequate headroom for the reflected voltage and leakage inductance spikes, provided the switching loop inductance is controlled. The 1 V saturation at 3 A (Vce(sat) max at 600 mA base current) keeps conduction losses manageable for a 4 A device, though the 12 minimum DC current gain at 500 mA means the base drive needs to be sized for forced-beta operation in saturation.","metaTitle":"BUJ103AX,127 NPN Power Transistor, 400 V, 4 A, TO-220F","metaDescription":"BUJ103AX,127 NPN power bipolar transistor from Ween Semiconductors. 400 V Vceo, 4 A Ic, 26 W power dissipation in TO-220F isolated tab.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Logic ICs"],"specifications":{"Package":"Bulk","Power - Max":"26 W","Mounting Type":"Through Hole","Package / Case":"TO-220-3 Full Pack, Isolated Tab","Transistor Type":"NPN","lifecycle_stage":"eol_hot","Operating Temperature":"150°C (TJ)","Supplier Device Package":"TO-220F","Vce Saturation (Max) @ Ib, Ic":"1V @ 600mA, 3A","Current - Collector (Ic) (Max)":"4 A","Current - Collector Cutoff (Max)":"100µA","DC Current Gain (hFE) (Min) @ Ic, Vce":"12 @ 500mA, 5V","Voltage - Collector Emitter Breakdown (Max)":"400 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$0.4","stockQuantity":0,"priceTiers":[{"qty":760,"price":"$0.40000","currency":"USD"}]},"links":{"datasheetUrl":"https://cdn.icboms.com/59e9139f9efb6f94f2ffd1faba28bc2c.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is a suitable replacement for BUJ103AX,127?","answer":"No official replacement or second-source alternate is listed by the manufacturer for this part. For a drop-in alternative, look for an NPN power transistor in TO-220F with a 400 V Vceo rating and 4 A collector current — parts from STMicroelectronics (e.g., the 2N3771 family) or ON Semiconductor may fit, but verify pinout and thermal specs against your design."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://icboms.com/nxp/BUJ103AX127","citationPolicyUrl":"https://icboms.com/llms.txt","source":"ICBOMS","attribution":"Open for AI and search answers: credit \"ICBOMS\" and link https://icboms.com/nxp/BUJ103AX127 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}}