BD238 PNP Transistor Pinout Datasheet

Introduction

The BD238 is a PNP silicon epitaxial-base power transistor designed for medium-power linear amplification and switching applications. Its PNP polarity makes it suited for circuits needing negative-side conduction or for use in complementary amplifier stages. It is packaged in a TO-126 / SOT-32 plastic package, providing a compact footprint while still supporting moderate thermal dissipation.

This transistor is manufactured using planar technology and often described as having a “Base-Island” layout, which helps provide high DC gain performance and low saturation voltage. Because it is the complementary partner to the BD237, it is widely used in push-pull amplifier designs and class AB output stages. The BD238 is also useful in switching circuits where PNP conduction is required (for example on the high side), and in analog circuits needing matched PNP devices.

BD238 PNP Transistor

In practical electronics, the BD238 is chosen in designs where one needs a PNP device with good voltage tolerance, moderate current capacity, and stable gain. It is common in audio amplifiers, driver stages, and general-purpose circuits where symmetry or dual-polarity operation is needed.

Pinout of BD238

Key Features

• PNP transistor for complementary or negative conduction circuits
• High DC current gain in the medium-power class
• Low saturation voltage for efficient conduction
• Compact TO-126 package compatible with modest heatsinking
• Suitable for use in complementary amplifier stages
• Reliable in both switching and linear roles

Specifications/Characteristics

• Collector-Base Breakdown Voltage, VCBO = –100 V
• Collector-Emitter Breakdown Voltage, VCEO = –80 V
• Collector-Emitter Sustaining Voltage, VCE(sus) = –80 V (for IC = 100 mA)
• Emitter-Base Breakdown Voltage, VEBO = –5 V
• Collector Current, Continuous IC = –2 A
• Collector Peak (Pulse) Current, ICM = –6 A
• Total Power Dissipation, Ptot = 25 W (at case temperature = 25 °C)
• Maximum Junction Temperature, Tj = 150 °C
• Storage Temperature Range, Tstg = –65 to +150 °C
• Thermal Resistance, Junction-to-Case, θJC = 5 °C/W
• Collector Cut-Off Current, ICBO ≤ 0.1 mA (at VCB = –100 V, IE = 0)
• Emitter Cut-Off Current, IEBO ≤ 1.0 mA (at VEB = –5 V, IC = 0)
• Collector-Emitter Saturation Voltage, VCE(sat) = –0.6 V (for IC = –1 A, IB = –0.1 A)
• Base-Emitter On Voltage, VBE(on) = –1.3 V (for IC = –1 A, VCE = –2 V)
• DC Current Gain, hFE = 40 (for IC = –150 mA, VCE = –2 V)
• DC Current Gain, hFE = 25 (for IC = –1 A, VCE = –2 V)
• Transition Frequency, fT = 3 MHz (for IC = –250 mA, VCE = –10 V)

Pin Configuration

Comparison Summary of BD234 vs BD236 vs BD238

• BD234 is the lowest-voltage PNP transistor in this series, with a collector-emitter rating of –45 V, making it ideal for low-to-medium voltage PNP circuits.
• BD236 increases that rating to –60 V, providing more flexibility for circuits with higher supply voltages while retaining the same current/power characteristics.
• BD238 has the highest voltage tolerance, rated at –80 V (and –100 V from collector to base), making it suited for more demanding or high-voltage PNP applications.
• All three share identical continuous current rating of –2 A, peak current of –6 A, and power dissipation of 25 W, so their capabilities in current handling and power are the same. Their gain (hFE) and frequency response (3 MHz) are also comparable, allowing them to be interchanged in designs where the voltage requirement is the deciding factor.

More Circuit Layouts

Key Applications of BD238 PNP Transistor

• Push-pull complementary amplifier stages
• Audio amplifier driver and output circuits
• High-side switching or PNP side driver circuits
• Analog switching and control circuits requiring PNP devices
• General-purpose PNP power transistor roles in medium-power systems

NPN Complimentary Transistor

• The complementary NPN transistor for BD238 is BD237.

Equivalent Transistors of BD238 PNP Transistor

Some possible equivalents or alternative PNP power transistors include:

• BD236 (for lower voltage use)
• BD234 (for still lower voltage)
• Other PNP transistors in the same class (2 A, 25 W, 80–100 V)
• General-purpose PNP power transistors with matching voltage and current capabilities

(Pin configuration of some transistors mentioned here may different from BD238).

Datasheet of BD238 PNP Transistor

Click the following Button to download the datasheet of BD238 Transistor :

More projects, You may like:

• Video Transmitter DIY Homemade FM Radio Transmitter
• Adjustable Power Supply DIY Battery Charger
• 12V-220V 500 Watt inverter DIY Homemade
• MPPT Solar Charge Controller DIY Homemade
• DIY LA4440 bass amplifier homemade

For more project and circuit diagrams, you can go through the Schematics in the main menu where you can find many interesting projects and circuit diagrams like audio amplifier circuits, voltage booster circuit, battery charger circuit and timer circuits etc., which are all beginner circuit projects. Feel free to check them out!

Thank you for visiting the article.