BD679

BD679 Series NPN Power Transistor Technical Summary

Overview

The BD679 is part of a series of silicon epitaxial-base NPN power transistors designed for medium-power applications requiring robust performance and reliability. This component belongs to a family that includes the BD677, BD677A, BD679, BD679A, and BD681, each offering variations in voltage, current, and power handling capabilities. The BD679 is particularly suited for applications demanding high current gain and low saturation voltage, making it ideal for power amplification, switching, and linear regulation tasks.

Manufactured using advanced epitaxial-base technology, the BD679 ensures excellent thermal stability and efficient power dissipation. Its construction allows for operation in demanding environments, with a robust package that enhances heat dissipation and mechanical durability. The transistor is commonly used in audio amplifiers, power supply circuits, and motor control systems.

Features

• High Current Capability: The BD679 can handle collector currents up to 4A, making it suitable for medium-power applications.
• Low Saturation Voltage: Features a low V_CE(sat), ensuring efficient operation in switching applications.
• High Voltage Tolerance: Supports collector-emitter voltages up to 80V, providing flexibility in various circuit designs.
• Excellent Gain Characteristics: Offers a high DC current gain (h_FE), typically ranging from 40 to 250, depending on operating conditions.
• Robust Thermal Performance: Designed with a power dissipation capability of up to 40W, coupled with a TO-126 package for effective heat management.
• Complementary PNP Options: Available with complementary PNP transistors (e.g., BD680) for push-pull and other symmetrical circuit configurations.

Applications

The BD679 is widely used in both industrial and consumer electronics due to its versatile performance characteristics. Key application areas include:

• Audio Amplifiers: Used in output stages of audio amplifiers due to its high current and voltage handling capabilities.
• Power Supplies: Employed in linear regulators and switching power supplies for efficient voltage regulation.
• Motor Control: Suitable for driving small to medium DC motors in appliances and automotive systems.
• Switching Circuits: Ideal for relay drivers, solenoid controllers, and other high-current switching applications.
• General-Purpose Amplification: Used in signal amplification stages where medium power handling is required.

Electrical Characteristics

The following table summarizes the key electrical specifications of the BD679 under typical operating conditions (T_A = 25°C unless otherwise noted):

• Collector-Emitter Voltage (V_CEO): 80V
• Collector-Base Voltage (V_CBO): 100V
• Emitter-Base Voltage (V_EBO): 5V
• Continuous Collector Current (I_C): 4A
• Total Power Dissipation (P_tot): 40W (at T_C = 25°C)
• DC Current Gain (h_FE): 40 to 250 (at I_C = 500mA, V_CE = 2V)
• Collector-Emitter Saturation Voltage (V_CE(sat)): 0.5V (max) at I_C = 2A, I_B = 0.2A
• Transition Frequency (f_T): 3MHz (typical)

Package Information

The BD679 is housed in a TO-126 package, which provides a balance between compact size and thermal performance. Key package details include:

• Package Type: TO-126 (SOT-32)
• Mounting Style: Through-hole
• Pin Configuration:
  • Pin 1: Emitter (E)
  • Pin 2: Collector (C)
  • Pin 3: Base (B)
• Thermal Resistance:
  • Junction-to-Ambient (R_θJA): 62.5°C/W
  • Junction-to-Case (R_θJC): 3.125°C/W
• Weight: Approximately 1.2 grams
• Operating Temperature Range: -65°C to +150°C

Reliability and Compliance

The BD679 is designed to meet stringent quality and reliability standards, ensuring long-term performance in demanding applications. It complies with industry standards for electrical and thermal performance, and it is suitable for use in commercial, industrial, and automotive environments. The device is also RoHS compliant, adhering to environmental regulations.

Conclusion

The BD679 NPN power transistor is a versatile and reliable component for medium-power applications. Its combination of high current capability, low saturation voltage, and robust thermal performance makes it an excellent choice for audio amplification, power regulation, and switching circuits. With its TO-126 package and wide operating temperature range, the BD679 is well-suited for both consumer and industrial electronics.