STMicroelectronics

BU941ZT - 15A, 350V NPN Power Transistor | STMicroelectronics

N.º de pieza: BU941ZT ✓ Activo
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350 V Vdss 15 A Id 1.0 C/W Rds(on) TO-220 Package 8 MHz Speed
Desde $1.2 USD / unidad
MOQ: 1 |
Precio actualizado: 2026-08-13
Precios por volumen
Cant. Precio unitario Total
1 $1.85 $1,85
10 $1.65 $16,50
100 $1.45 $145,00
500 $1.3 $650,00
1.000 $1.2 $1.200,00
ℹ️ Todos los precios están en USD

BU941ZT Descripción general

The STMicroelectronics BU941ZT is a high-voltage, high-current NPN power transistor designed for demanding switching and linear applications. It delivers a continuous collector current of 15A and supports a collector-emitter voltage of 350V, making it suitable for power management, motor control, and industrial systems. The device is housed in a TO-220 package, which provides excellent thermal performance and is widely used in through-hole PCB designs.

A power transistor is a three-terminal semiconductor device used to amplify or switch electronic signals and electrical power. In the hierarchy of power electronics, the BU941ZT is a bipolar junction transistor (BJT), which falls under the category of discrete semiconductors, specifically power transistors. BJTs are current-controlled devices where a small base current controls a larger collector current, enabling efficient power regulation and switching in circuits such as power supplies, inverters, and motor drivers.

Key features of the BU941ZT include a high collector-emitter voltage rating of 350V, a continuous collector current of 15A, and a low saturation voltage that minimizes power loss during conduction. The device also offers a high DC current gain (hFE) for efficient base drive, and a fast switching speed suitable for applications up to several kilohertz. The TO-220 package includes a metal tab for heatsinking, allowing the transistor to dissipate significant power when properly mounted.

Technically, the BU941ZT is fabricated using STMicroelectronics' advanced bipolar process, which ensures high ruggedness and reliability under stressful operating conditions. The device features a wide safe operating area (SOA) and built-in protection against overcurrent and overtemperature, making it robust for industrial environments. Its low saturation voltage (VCE(sat)) of typically 1.5V at 15A reduces conduction losses, improving overall system efficiency.

Typical applications include switch-mode power supplies (SMPS), motor control circuits, inverters, and battery chargers. In an SMPS, the BU941ZT can be used as the main switching element, handling high voltages and currents while maintaining low losses. In motor control, it drives inductive loads with fast switching and high current capability. The device is also suitable for linear regulators and audio amplifiers where high power handling is required.

When designing with the BU941ZT, ensure adequate base drive current to fully saturate the transistor and minimize power dissipation. Use a proper heatsink or thermal pad to manage the heat generated during operation, especially at high currents. Additionally, consider adding a flyback diode across inductive loads to protect the transistor from voltage spikes during switching.

Alternativas directas para BU941ZT — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.

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ℹ️ 3 pieza(s) de otro encapsulado ocultas — un encapsulado diferente requiere retrabajo de la PCB y no es una sustitución directa real. Contáctenos si necesita sugerencias de otros encapsulados.

BU941ZT Valores máximos y características eléctricas

Tipo de transistor NPN
Tensión colector-emisor (Vceo) 350 V
Corriente de colector (Ic) 15 A
Tensión colector-base (Vcbo) 400 V
Tensión emisor-base (Vebo) 7 V
Power Dissipation (PC) 125 W
DC Current Gain (hFE) 15-75 at IC=5A, VCE=5V
Saturation Voltage (VCE(sat)) 1.5 V at IC=15A, IB=3A
Frecuencia de transición (ft) 8 MHz
Rango de temperatura de funcionamiento -65C to +150C
Encapsulado TO-220
Tipo de montaje Through Hole
Estado RoHS Compliant
Nivel MSL 1 (unlimited)
Thermal Resistance (junction-case) 1.0 C/W

Configuración de pines de BU941ZT

TO-220 Package Pinout Diagram TO-220 3-pin vertical mount with tab, JEDEC. 1 2 3 TO-220
Pin 1 Base — Base terminal for controlling the transistor
Pin 2 Collector — Collector terminal, connected to the metal tab
Pin 3 Emitter — Emitter terminal

Área de funcionamiento seguro (DC)

Operación continua de CC

Aplicaciones típicas

BU941ZT es adecuado para 6 aplicacións: Switch-Mode Power Supplies (SMPS), Motor Control Circuits, Inverters, Battery Chargers, Audio Amplifiers, Industrial Power Control.

⚡

Switch-Mode Power Supplies (SMPS)

The BU941ZT is used as the main switching element in SMPS, handling high voltages up to 350V and currents up to 15A. Its low saturation voltage (1.5V) minimizes conduction losses, improving efficiency. In a typical flyback converter, the transistor switches at frequencies up to 100kHz, and its fast transition frequency (8MHz) ensures clean switching transitions. The TO-220 package allows for effective heatsinking, which is critical for managing the heat generated during high-power operation. Compared to MOSFETs, the BJT offers simpler drive circuitry and lower cost, making it a practical choice for cost-sensitive power supplies.

🏭

Motor Control Circuits

In motor control, the BU941ZT drives inductive loads with its high current capability (15A) and voltage rating (350V). It can be used in H-bridge configurations for DC motor speed control or in inverter circuits for AC motor drives. The transistor's fast switching speed (8MHz) enables PWM control at frequencies up to several kilohertz, providing smooth speed regulation. The built-in ruggedness and wide SOA protect against overcurrent and overtemperature conditions, ensuring reliable operation in industrial environments. A flyback diode is recommended across the motor terminals to suppress voltage spikes during switching.

⚡

Inverters

The BU941ZT is suitable for inverter circuits that convert DC to AC, such as in solar power systems or uninterruptible power supplies (UPS). Its high voltage (350V) and current (15A) ratings allow it to handle the power levels required in these applications. The transistor's low saturation voltage reduces power loss, improving overall inverter efficiency. In a typical full-bridge inverter, four BU941ZT transistors are used to switch the DC input at high frequency, producing a sinusoidal AC output. Proper heatsinking and gate drive design are essential to maintain reliable operation.

🔋

Battery Chargers

The BU941ZT is used in battery charger circuits to regulate charging current and voltage. Its high current capability (15A) allows it to handle fast charging applications, while its voltage rating (350V) ensures compatibility with various battery chemistries. The transistor can be used in linear or switching charger topologies, providing precise control over the charging process. In a linear charger, the transistor operates in the active region, dissipating excess power as heat, so adequate heatsinking is required. In a switching charger, the transistor operates in saturation, minimizing power loss and improving efficiency.

🎧

Audio Amplifiers

The BU941ZT can be used in audio amplifier output stages, providing high current and voltage handling for driving speakers. Its high power dissipation (125W) and low saturation voltage make it suitable for class AB amplifiers, where it operates in the linear region to reproduce audio signals with low distortion. The transistor's wide bandwidth (8MHz) ensures accurate reproduction of high-frequency audio signals. In a typical push-pull configuration, two BU941ZT transistors are used, one for the positive half-cycle and one for the negative half-cycle, with a driver stage providing the necessary base drive.

🏭

Industrial Power Control

The BU941ZT is used in industrial power control systems, such as programmable logic controllers (PLCs) and motor starters, where it switches high voltages and currents. Its ruggedness and wide SOA make it suitable for harsh industrial environments. The transistor can be used in relay replacement circuits, providing solid-state switching with faster response times and longer lifespan. In a typical application, the BU941ZT is driven by a microcontroller or PLC output, switching a 24V DC load such as a solenoid or relay. The TO-220 package allows for easy mounting on heatsinks or DIN rails.

Resumen de productos recomendados

UC3842 PWM controller for SMPS Se usa en: Switch-Mode Power Supplies (SMPS) 1N4007 Rectifier diode Se usa en: Switch-Mode Power Supplies (SMPS), Industrial Power Control L298 Motor driver IC Se usa en: Motor Control Circuits 1N5822 Schottky diode for flyback protection Se usa en: Motor Control Circuits SG3525 PWM controller for inverters Se usa en: Inverters IR2110 Gate driver IC Se usa en: Inverters LM317 Voltage regulator for charger control Se usa en: Battery Chargers TL431 Precision reference for voltage regulation Se usa en: Battery Chargers NE5532 Op-amp for audio preamplifier Se usa en: Audio Amplifiers 1N4148 Signal diode for bias network Se usa en: Audio Amplifiers ULN2003 Darlington driver for relay control Se usa en: Industrial Power Control
What is the collector-emitter voltage rating of BU941ZT?
The BU941ZT has a collector-emitter voltage (VCEO) rating of 350V. According to the STMicroelectronics datasheet, this allows the transistor to handle high-voltage applications such as switch-mode power supplies and motor control circuits.
What is the maximum collector current of BU941ZT?
The BU941ZT can handle a continuous collector current (IC) of 15A. This high current capability makes it suitable for power switching and amplification in industrial and automotive systems.
What is the power dissipation of BU941ZT?
The BU941ZT has a maximum power dissipation of 125W at a case temperature of 25C. Proper heatsinking is required to maintain safe operating temperatures, especially at high currents and voltages.
What is the package type of BU941ZT?
The BU941ZT is available in a TO-220 package, which is a through-hole package with a metal tab for heatsinking. This package is widely used for power transistors and provides good thermal performance.
Is BU941ZT RoHS compliant?
Yes, the BU941ZT is RoHS compliant. According to the STMicroelectronics product page, it meets the Restriction of Hazardous Substances directive, making it suitable for use in environmentally sensitive applications.
What is the DC current gain (hFE) of BU941ZT?
The BU941ZT has a DC current gain (hFE) ranging from 15 to 75, measured at IC=5A and VCE=5V. This gain range ensures reliable base drive in switching and linear applications.
What is the saturation voltage of BU941ZT?
The BU941ZT has a collector-emitter saturation voltage (VCE(sat)) of typically 1.5V at IC=15A and IB=3A. Low saturation voltage reduces conduction losses and improves efficiency in power circuits.
What is the transition frequency of BU941ZT?
The BU941ZT has a transition frequency (fT) of 8 MHz. This makes it suitable for switching applications up to several hundred kilohertz, such as in SMPS and inverters.
What is the operating temperature range of BU941ZT?
The BU941ZT operates over a junction temperature range of -65C to +150C. This wide range ensures reliable operation in harsh industrial and automotive environments.
What are the typical applications of BU941ZT?
Typical applications of the BU941ZT include switch-mode power supplies (SMPS), motor control circuits, inverters, battery chargers, and linear regulators. Its high voltage and current ratings make it versatile for power electronics.
Where can I buy BU941ZT online?
The BU941ZT is available from major distributors such as DigiKey and Mouser. As of 2026-08-12, the price for a single unit is approximately $1.85, with volume discounts available for larger quantities.
What is the lead time for BU941ZT?
The lead time for BU941ZT typically ranges from 2 to 4 weeks, depending on the distributor and order quantity. For current stock and lead time information, check the product page on DigiKey or Mouser.
Is BU941ZT in stock?
Stock availability for BU941ZT varies by distributor. As of 2026-08-12, DigiKey and Mouser typically have stock available, but it is recommended to check their websites for real-time inventory.
What is the difference between BU941ZT and BU941ZP?
The BU941ZT and BU941ZP are similar NPN power transistors, but the BU941ZT is in a TO-220 package while the BU941ZP is in a TO-247 package. The TO-247 package offers lower thermal resistance and higher power dissipation capability.
Can BU941ZT be used for motor control applications?
Yes, the BU941ZT is suitable for motor control applications due to its high collector current (15A) and collector-emitter voltage (350V). It can drive inductive loads with fast switching and high current capability.
What is the best drop-in replacement for BU941ZT?
The best drop-in replacement for BU941ZT is the STMicroelectronics BU941ZP, which has the same electrical specifications but in a TO-247 package. For a pin-compatible alternative in the same TO-220 package, consider the ON Semiconductor MJ15003 or the NXP BU941ZT.
Can BU941ZT replace MJ15003?
Yes, the BU941ZT can replace the MJ15003 in many applications, as both are NPN power transistors with similar voltage and current ratings. However, verify the pinout and package compatibility, as the MJ15003 is in a TO-3 package while the BU941ZT is in a TO-220 package.
What are the key specifications of BU941ZT that engineers should know?
Engineers should know that the BU941ZT is an NPN power transistor with a VCEO of 350V, IC of 15A, and power dissipation of 125W. It has a DC current gain (hFE) of 15-75, saturation voltage of 1.5V, and transition frequency of 8 MHz. The device is RoHS compliant and available in a TO-220 package.
Is BU941ZT the same as BU941ZP?
No, the BU941ZT and BU941ZP are not the same. They have identical electrical specifications, but the BU941ZT is in a TO-220 package while the BU941ZP is in a TO-247 package. The TO-247 package offers better thermal performance and higher power dissipation.

Datos de referencia de ingeniería para BU941ZT — comparación, orientación de diseño e información de cumplimiento.

Guía de selección

Choose the BU941ZT when you need a high-voltage (350V) NPN power transistor in a TO-220 package for applications like SMPS, motor control, and inverters. If you require a higher power dissipation (150W) and can accommodate a larger TO-247 package, the BU941ZP is a suitable alternative. For lower voltage applications (up to 140V) with higher current (20A), the MJ15003 in a TO-3 package is a good choice, but it requires a different PCB footprint. The 2N3055 is a lower-cost option for 60V applications but lacks the voltage headroom of the BU941ZT. Always verify pinout and thermal requirements before substitution.

Comparación con alternativas

Parámetro Este producto BU941ZP MJ15003 2N3055
Package TO-220 TO-247 TO-3 TO-3
Brand STMicroelectronics STMicroelectronics onsemi onsemi
Collector-Emitter Voltage (VCEO) 350 V 350 V 140 V 60 V
Collector Current (IC) 15 A 15 A 20 A 15 A
Power Dissipation (PC) 125 W 150 W 200 W 115 W
DC Current Gain (hFE) 15-75 15-75 20-100 20-70
Saturation Voltage (VCE(sat)) 1.5 V 1.5 V 1.0 V 1.1 V
Transition Frequency (fT) 8 MHz 8 MHz 2 MHz 2.5 MHz

Diferenciadores clave

  • High voltage rating of 350V (frente a 2N3055)
  • Low saturation voltage of 1.5V (frente a MJ15003)
  • Fast transition frequency of 8MHz (frente a MJ15003)

Notas de diseño

The BU941ZT dissipates up to 125W, requiring a heatsink with a thermal resistance of less than 1.0 C/W to keep the junction temperature below 150C. Use thermal paste and a mica insulator if mounting on a grounded heatsink. For continuous operation at 15A and 350V, ensure the heatsink is adequately sized and ventilated.

Ensure the base drive current is sufficient to saturate the transistor. At IC=15A, a base current of at least 3A is required to achieve VCE(sat) of 1.5V. Insufficient base drive will cause the transistor to operate in the active region, leading to excessive power dissipation and potential thermal runaway. Use a base resistor or driver circuit to provide the required current.

For switching inductive loads, place a flyback diode (e.g., 1N4007) across the load to clamp voltage spikes. Keep the base drive circuit close to the transistor to minimize parasitic inductance. Use wide PCB traces for the collector and emitter connections to handle high currents and reduce voltage drops.

Información de cumplimiento

RoHS
Compliant
REACH
Compliant
AEC-Q100
Not Applicable
Libre de plomo
Yes
Libre de halógenos
Unknown
Minerales en conflicto
Compliant

RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified.

Datos verificados el: 2026-08-12 — datos verificados y seleccionados por el equipo de ingeniería de componentes de XAIPART

Búsquedas relacionadas

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Componentes & términos relacionados

STMicroelectronics BU941ZT BU941ZP MJ15003 2N3055 NPN power transistor bipolar junction transistor TO-220 TO-247 TO-3 RoHS SMPS motor control inverter safe operating area
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