BD236 NPN Power Transistor

Overview

The BD236 is a silicon epitaxial-base NPN power transistor designed for general-purpose amplifier and switching applications. It is part of the BD23x series, which includes complementary PNP types (BD235, BD237) and is housed in a robust Jedec SOT-32 plastic package. This transistor is characterized by its high current capability, low saturation voltage, and excellent thermal stability, making it suitable for a wide range of industrial and consumer electronics applications.

The BD236 is particularly well-suited for use in power amplification stages, voltage regulators, and motor control circuits due to its ability to handle significant power dissipation while maintaining reliable performance. Its construction ensures consistent operation under varying load conditions, and it is often used in linear and switching power supplies, audio amplifiers, and other medium-power applications.

Features

• High Current Capability: Collector current (Ic) up to 2A, making it suitable for medium-power applications.
• Low Saturation Voltage: V_CE(sat) typically 0.5V at Ic = 1.5A, ensuring efficient switching performance.
• High Power Dissipation: Capable of dissipating up to 25W (with adequate heat sinking).
• Wide Operating Temperature Range: -65°C to +150°C, allowing use in harsh environments.
• Complementary PNP Pair Available: BD235 (PNP counterpart) for push-pull configurations.
• High Gain Bandwidth Product: Suitable for audio and low-frequency amplification.
• Robust Package: Jedec SOT-32 plastic case provides mechanical durability and thermal performance.

Applications

The BD236 is widely used in both industrial and consumer electronics due to its versatile performance characteristics. Below are some common applications:

• Power Amplifiers: Used in audio and RF amplification stages where medium power handling is required.
• Voltage Regulators: Acts as a pass transistor in linear voltage regulator circuits.
• Motor Control: Suitable for driving small DC motors in appliances and automotive systems.
• Switching Circuits: Efficiently handles on/off switching in power supply and relay driver applications.
• LED Drivers: Provides current regulation in high-power LED lighting systems.
• General-Purpose Switching: Used in relay drivers, solenoid controls, and other switching applications.

Electrical Characteristics

The following table summarizes the key electrical parameters of the BD236 under typical operating conditions (unless otherwise specified):

Absolute Maximum Ratings

• Collector-Emitter Voltage (V_CEO): 45V
• Collector-Base Voltage (V_CBO): 60V
• Emitter-Base Voltage (V_EBO): 5V
• Collector Current (I_C): 2A (continuous)
• Total Power Dissipation (P_tot): 25W (at T_case = 25°C)
• Operating Junction Temperature (T_j): -65°C to +150°C
• Storage Temperature (T_stg): -65°C to +150°C

Typical Electrical Characteristics (T_j = 25°C)

• DC Current Gain (h_FE): 40 - 250 (at I_C = 500mA, V_CE = 2V)
• Collector-Emitter Saturation Voltage (V_CE(sat)): 0.5V (max) at I_C = 1.5A, I_B = 150mA
• Base-Emitter Saturation Voltage (V_BE(sat)): 1.2V (max) at I_C = 1.5A, I_B = 150mA
• Transition Frequency (f_T): 3MHz (typical)
• Output Capacitance (C_obo): 100pF (typical at V_CB = 10V, f = 1MHz)

Package Information

The BD236 is housed in a Jedec SOT-32 (TO-126) plastic package, which provides a balance between compact size and thermal performance. The package is designed for through-hole mounting and includes a metal tab for optional heat sinking.

Package Dimensions

• Total Height: 9.5mm (max)
• Lead Length: 3.8mm (min)
• Lead Spacing: 5.2mm (between emitter and collector)
• Mounting Hole Diameter: 3.2mm (recommended)

Thermal Characteristics

• Thermal Resistance, Junction-to-Case (R_th(j-c)): 3.125°C/W
• Thermal Resistance, Junction-to-Ambient (R_th(j-a)): 62.5°C/W (without heat sink)

Conclusion

The BD236 is a reliable and versatile NPN power transistor suitable for a broad range of medium-power applications. Its combination of high current handling, low saturation voltage, and robust thermal performance makes it an excellent choice for designers working on power amplification, switching, and voltage regulation circuits. The SOT-32 package ensures ease of mounting while providing adequate heat dissipation when used with a heat sink. Whether used in consumer electronics, industrial controls, or automotive systems, the BD236 delivers consistent performance under demanding conditions.