STMicroelectronics

BU941

BU941 Description

The BU941 from STMicroelectronics is a high-power NPN Darlington transistor designed for demanding applications requiring robust performance. Encased in a TO-3 package, it features a 400V collector-emitter breakdown voltage (V_CEO) and a 15A maximum collector current (I_C), making it suitable for high-voltage, high-current switching and amplification. With a 180W power dissipation rating and an operating temperature range of up to 200°C (T_J), the BU941 excels in harsh environments. Its low collector cutoff current (100µA max) and high DC current gain (h_FE ≥ 300 @ 5A, 10V) ensure efficient operation with minimal leakage.

BU941 Features

• High Voltage & Current Handling: 400V V_CEO and 15A I_C for power applications.
• Low Saturation Voltage: 2V max @ 300mA, 12A, reducing power losses.
• High Gain Darlington Pair: h_FE ≥ 300 ensures strong signal amplification.
• Robust Thermal Performance: 180W power dissipation and 200°C T_J for reliability.
• Chassis Mount (TO-3): Ideal for heat dissipation in high-power systems.
• Compliance: ROHS3 Compliant, REACH Unaffected, and EAR99 ECCN for global use.

BU941 Applications

The BU941 is ideal for:

• Power Supplies: High-voltage switching in industrial SMPS.
• Motor Control: Driving high-current motors in automation and robotics.
• Audio Amplifiers: High-power output stages in professional audio systems.
• Industrial Equipment: Relays, solenoids, and inductive load switching.
• Automotive Systems: Ignition systems and high-power electronic controls.

Conclusion of BU941

The BU941 stands out as a high-reliability Darlington transistor for high-voltage, high-current applications. Its low saturation voltage, high gain, and robust thermal performance make it superior to standard bipolar transistors in demanding environments. While obsolete, its TO-3 chassis mount and STMicroelectronics' legacy quality ensure it remains a viable choice for legacy designs or replacements. Ideal for industrial, automotive, and audio applications, the BU941 delivers durable performance where efficiency and power handling are critical.