BUX48 - 400V 15A 175W NPN Power Transistor | STMicroelectronics
부품 번호: BUX48 ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $5.2 | $5.20 |
| 10 | $4.78 | $47.80 |
| 100 | $4.3 | $430.00 |
| 500 | $3.95 | $1,975.00 |
| 1,000 | $3.6 | $3,600.00 |
BUX48 개요
A high-voltage NPN power BJT is a three-terminal semiconductor amplifier and switch in the broader hierarchy: bipolar junction transistor -> power transistor -> discrete power semiconductor. Unlike MOSFETs, BJTs are current-controlled devices, and the multi-epitaxial mesa construction of the BUX48 family gives it a combination of high breakdown voltage and fast switching speed that was specifically engineered for off-line switch-mode power supplies.
Key features include a 400V collector-emitter breakdown rating, 15A maximum collector current, 175W total power dissipation at a properly heatsunk case, and fast switching characteristics suited to SMPS half-bridge and forward converter stages. The metal TO-3 package provides very low thermal resistance from junction to case and excellent mechanical robustness for chassis mounting.
Technically, the device uses multi-epitaxial mesa technology to achieve high collector-emitter voltage capability while preserving fast turn-off. This makes it well matched to hard-switching and quasi-resonant converter topologies operating directly from rectified 110V/230V mains, where 400V-class blocking voltage is required.
Typical applications include offline switch-mode power supplies, flyback and forward converters, motor control and industrial power switching, and high-voltage inverter stages for single- and three-phase mains-powered equipment.
Design consideration: because the collector is electrically connected to the TO-3 metal can, the case must be isolated from the chassis heatsink with a mica washer and insulated bushings, and base drive must supply enough forced beta to keep VCE(sat) low at full load.
This page adds distributor pricing, drop-in alternatives, comparison tables, and practical design notes not found in the manufacturer datasheet.
드롭인 대체품: BUX48 — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
BUX48A
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
BUX48B
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
BUX48C
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
2N6547
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
MJ10001
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
2SC3058
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
BUX48 최대 정격 & 전기적 특성
| 트랜지스터 유형 | NPN Bipolar Junction Transistor (BJT) |
| Collector-Emitter Breakdown Voltage (VCEO) | 400 V |
| Continuous Collector Current (IC) | 15 A |
| Total Power Dissipation (Ptot) | 175 W |
| Technology | Multi-epitaxial mesa |
| 패키지 | TO-3 metal can, chassis mount |
| 실장 유형 | Through-Hole / Chassis Mount |
| Intended Applications | High-voltage fast switching, single- and three-phase mains SMPS and industrial |
| Complementary Variant | BUX48A (450 V version) |
BUX48 핀 구성
| 핀 1 | Emitter — Emitter terminal (pin 1 of the TO-3 can) |
| 핀 2 | Base — Base terminal - control input for collector current |
| 핀 Case | Collector — Collector connected internally to the TO-3 metal can; isolate from heatsink with mica washer |
안전 동작 영역 (approximate, DC)
일반적인 애플리케이션
BUX48 적합 용도: 6 애플리케이션s: Offline Switch-Mode Power Supplies, Industrial Motor Control and Power Switching, Three-Phase Mains Converter Stages, Legacy Equipment Repair and Maintenance, High-Voltage Linear and Series Pass Stages, Inverters and Induction Heating Drivers.
Offline Switch-Mode Power Supplies
The BUX48's 400V blocking voltage and multi-epitaxial mesa fast-switching construction make it a natural fit for the main power switch in offline SMPS half-bridge, forward, and flyback converters fed from rectified single-phase mains. In a typical 230V AC design, the rectified bus sits near 325V, leaving modest but real headroom under the 400V VCEO rating for leakage-inductance spikes when snubbers and clamps are fitted. The 15A / 175W capability covers converter outputs from several hundred watts up to roughly a kilowatt. As a BJT, it requires proportional base drive with negative base turn-off current for fast, clean switching; its TO-3 case must be isolated from the grounded heatsink with a mica washer because the collector is the metal can.
추천
Industrial Motor Control and Power Switching
In industrial equipment powered from single- and three-phase mains, the BUX48 serves as a high-voltage series switch, chopper, or inverter leg transistor. Its 15A continuous collector current and 175W dissipation capability with proper heatsinking handle solenoid, relay, DC motor, and small AC-drive switching loads directly from rectified mains. The rugged metal TO-3 package tolerates the vibration, thermal cycling, and high ambient temperatures typical of factory environments far better than plastic packages. Designers should provide forced-beta base drive so VCE(sat) stays low at peak load, fit freewheeling/snubber networks for inductive loads, and derate dissipation for high cabinet temperatures, since the 175W rating assumes case temperature is held near its specified reference point.
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Three-Phase Mains Converter Stages
The ST datasheet explicitly targets the BUX48 and BUX48A at applications from single- and three-phase mains, which includes three-phase rectified bus converters such as industrial welders, battery chargers, and DC links feeding choppers or inverters. A 380V/400V three-phase line rectifies to about 540V DC, so the BUX48's 400V rating suits it to the lower-voltage legs and auxiliary switching stages of such systems, or to 220V-class three-phase buses around 310V DC. The fast multi-epitaxial mesa process keeps turn-off tail and storage times manageable at converter frequencies of its era. Always verify that switching-frequency losses keep estimated junction temperature within the derated SOA for the specific bus voltage and load profile.
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Legacy Equipment Repair and Maintenance
A very large installed base of 1980s-2000s industrial power supplies, welders, UPS units, and laboratory instruments used the BUX48 as the main switching transistor. For repair work, the BUX48 remains the exact-fit part: the same TO-3 footprint, pin arrangement (emitter pin 1, base pin 2, case = collector), and drive requirements as the original design. The BUX48A is the preferred service substitute because it is electrically identical except for a higher 450V breakdown, providing free reliability margin in repaired units. When original-type stock is unavailable, cross-reference equivalents such as the 2N6547 or 2SC3058 fit the same TO-3 mounting, though hFE and switching times should be confirmed before substitution in timing-critical converters.
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High-Voltage Linear and Series Pass Stages
Although optimized for switching, the BUX48 also works as a series-pass element in high-voltage linear regulators and capacitor-charging circuits, where its 400V rating allows regulation directly from rectified mains or high-voltage DC buses. The 15A capability and 175W package rating support substantial continuous pass current when the pass transistor bank is mounted on generously sized heatsinks; for higher currents, devices can be paralleled with small emitter-ballast resistors to force current sharing. In linear duty, average dissipation equals the VIN-VOUT drop times load current, so Estimated worst-case dissipation should be computed at maximum bus voltage and minimum line condition before selecting heatsink size. Isolate the live collector can with mica hardware in grounded chassis.
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Inverters and Induction Heating Drivers
The BUX48's high-voltage rating and fast switching suit resonant inverters, induction-heating driver bridges, and high-voltage DC-AC conversion stages operating from rectified mains. In half-bridge and full-bridge topologies, each device blocks roughly the full DC bus, so the 400V VCEO targets 110/220V-derived buses while the BUX48A/B grade covers taller rails. The multi-epitaxial mesa structure provides the fast fall times needed to limit switching loss at the tens-of-kHz frequencies typical of resonant loads. Base drive must include anti-saturation techniques (Baker clamp or proportional drive) to minimize storage time, and each device needs an RC snubber to control turn-off voltage overshoot from transformer and bus parasitics.
추천
추천 제품 요약
엔지니어링 참조 데이터: BUX48 — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | BUX48A | BUX48B | 2N6547 | MJ10001 | 2SC3058 |
|---|---|---|---|---|---|---|
| Package | TO-3 metal can | TO-3 - same | TO-3 - same | TO-3 - same | TO-3 - same | TO-3 - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | onsemi | onsemi | Toshiba |
| Polarity / Technology | NPN multi-epitaxial mesa | NPN multi-epitaxial mesa | NPN | NPN | NPN | NPN |
| Primary Application | High-voltage fast switching, mains SMPS | Same family, higher voltage grade | Same family, higher voltage grade | High-voltage fast switching | High-voltage power switching | High-voltage switching (Japanese standard) |
주요 차별점
- Higher voltage margin in the same package (vs BUX48A)
- ST direct-family availability (vs 2N6547)
- Genuine fast-switching grading (vs MJ10001)
설계 노트
The 175W Ptot rating of the BUX48 assumes the TO-3 case is held near the datasheet-specified case temperature; it is not a free-air figure. Mount the device to a substantial chassis or finned heatsink with thermal grease, and derate dissipation linearly as case temperature rises. Estimated: at 50W dissipation with a typical 1 C/W heatsink plus a few C/W of junction-to-case resistance, the junction will run hot even at 40C ambient - always compute worst-case (maximum bus, minimum load resistance) before finalizing heatsink size.
The collector of the BUX48 is electrically bonded to the TO-3 metal can. In any grounded-chassis design, fit a mica insulating washer between the can and heatsink plus insulating shoulder bushings on the mounting screws, and verify isolation with a multimeter after assembly. Keep base and emitter leads short and twisted to reduce parasitic inductance, which otherwise causes voltage ringing on turn-off in hard-switched converters.
As a BJT, the BUX48 needs proportional base drive with a defined negative turn-off base current to exit saturation quickly; insufficient drive raises conduction loss (VCE(sat) losses) and excessive storage time lengthens turn-off and inflates switching loss. Use Baker-clamp or anti-saturation techniques in SMPS duty, add RC snubbers across the device to control leakage-inductance overshoot, and confirm the bus voltage plus overshoot stays below the 400V VCEO - or use the BUX48A for 50V extra margin.
규정 준수 정보
The retrieved distributor data (LCSC, DigiKey, Mouser) does not state a uniform RoHS/lead-free status for the BUX48 across manufacturers and date codes. Confirm compliance per the exact manufacturer and lot before use in RoHS-restricted products.
