BU508AF

The BU508AF is a high-voltage power transistor manufactured by STMicroelectronics, primarily designed for use in horizontal deflection circuits in color television sets and other applications requiring high-speed switching. Here’s a detailed description of its key features and specifications:

General Description:

The BU508AF is a NPN transistor that is housed in a TO-220 package, which is a common type of package for power transistors. This package allows for efficient heat dissipation, making it suitable for high-power applications.

Key Features:

1. High Voltage Rating: The BU508AF can handle a collector-emitter voltage (Vce) of up to 160V, making it suitable for high-voltage applications.
2. High Current Capability: It has a maximum collector current (Ic) rating of 5A, allowing it to drive significant loads.
3. Fast Switching Speed: The transistor is designed for fast switching, which is essential in applications like TV deflection circuits where rapid changes in current are required.
4. Power Dissipation: The device can dissipate up to 50W of power, depending on the thermal management and heat sinking used in the application.
5. Low Saturation Voltage: The BU508AF features a low saturation voltage, which improves efficiency and reduces heat generation during operation.

Electrical Characteristics:

• Collector-Emitter Voltage (Vce): 160V
• Collector Current (Ic): 5A
• Power Dissipation (Pd): 50W
• DC Current Gain (hFE): Typically ranges from 10 to 50, depending on the collector current.
• Transition Frequency (fT): Approximately 2.5 MHz, indicating its capability for high-frequency applications.

Applications:

• Television Deflection Circuits: Primarily used in the horizontal deflection stage of CRT televisions.
• Switching Power Supplies: Can be utilized in various power supply designs where high voltage and current handling are required.
• Motor Control: Suitable for driving motors in various applications due to its high current capacity.

Thermal Characteristics:

• The TO-220 package allows for effective heat dissipation, and the transistor should be mounted on a suitable heatsink to ensure reliable operation under high load conditions.

Conclusion:

The BU508AF from STMicroelectronics is a robust and versatile power transistor that excels in high-voltage and high-current applications. Its combination of fast switching capabilities, high power handling, and efficient thermal management makes it a popular choice in consumer electronics, particularly in older CRT-based devices.