BD203 NPN Transistor Pinout Datasheet

Introduction

The BD203 is an NPN silicon power transistor designed for medium-power amplification and switching applications. It’s commonly used in audio amplifier outputs, hi-fi circuits, and power driver stages. The device is built to handle relatively high currents and voltages for its class, making it suitable for kind of circuits where reliable power gain is needed. According to the datasheet, BD203 is packaged in a TO-220 style case and is intended for use in power amplifier equipment delivering in the range of 15 to 25 W into 4 Ω or 8 Ω loads.

In many amplifier designs, the BD203 serves as the NPN half of a complementary output stage, paired with a PNP transistor to form a push-pull output. The datasheet explicitly states that the PNP complements of the BD201/203 series are BD202 and BD204. Farnell+2cdn-reichelt.de+2 Since BD203 has a higher breakdown rating than BD201, it is used in circuits needing slightly more voltage headroom and robustness.

BD203 NPN Transistor

The BD203 transistor features low saturation voltage, wide safe operating area, and decent gain at higher currents (though not extremely fast). It is meant for stable operation in both linear amplifier use and switching roles in mid-power designs.

Pinout of BD203

Key Features

• Designed for medium-power audio amplification and switching
• Low collector-emitter saturation voltage
• Wide safe operating area for reliable performance
• Matched complementary pairing with BD204
• Robust thermal and mechanical package
• Suitable for hi-fi and audio output stages
• Good current-handling capability

Specifications/Characteristics

• Collector–Emitter Voltage (VCEO): 60V
• Collector–Base Voltage (VCBO): 60V
• Emitter–Base Voltage (VEBO): 5V
• Continuous Collector Current (IC): 8A
• Peak Collector Current (ICM): 12A (non-repetitive)
• Power Dissipation (Ptot): 60W at 25°C case temperature
• DC Current Gain (hFE): Minimum 30 at IC = 4A, VCE = 2V
• Transition Frequency (fT): 3 MHz typical
• Collector–Emitter Saturation Voltage (VCE(sat)): 1.5V at IC = 6A, IB = 0.6A
• Base–Emitter Saturation Voltage (VBE(sat)): 1.2V typical
• Thermal Resistance Junction-to-Case (RthJC): 2.1°C/W
• Operating and Storage Junction Temperature Range: –65°C to +150°C
• Package Type: TO-220
• Polarity: NPN Silicon Power Transistor

Pin Configuration

Comparison Summary of BD203 (NPN), BD204 (PNP)

• BD203 is an NPN power transistor, capable of handling 60 V and high currents, and is used on the positive-half side of complementary amplifier designs.
• BD204 is the PNP counterpart of BD203, used for the negative-half side in complementary output configurations.
• While both share similar voltage and current ratings, they operate with opposite polarity in circuits BD203 conducts when the base is driven positive, BD204 conducts when the base is driven negative relative to its emitter.
• In amplifier designs, BD203 + BD204 form a complementary pair to handle both halves of the waveform symmetrically, ensuring lower distortion and balanced output.

More Circuit Layouts

Key Applications of BD203 NPN Transistor

• Audio power amplifier output stages
• Push-pull complementary amplifier designs
• Medium-power switching circuits
• Driver stages for motors, relays, and solenoids in audio gear
• Power supply regulation and feedback circuits
• Hi-fi equipment delivering 15 to 25 W into low-impedance loads

PNP Complimentary Transistor

• The PNP complementary transistor of the BD203 is BD204.
  Both transistors are paired in push-pull output configurations and class AB amplifier stages, ensuring symmetric current handling and clean signal reproduction.

Equivalent Transistors of BD203 NPN Transistor

• BD201
• BD237
• BD239
• 2N3055
• TIP41A
• MJE3055
• 2N3772
• 2SD613
• BD243

(Pin configuration of some transistors mentioned here may different from BD203).

Datasheet of BD203 NPN Transistor

Click the following Button below to download the datasheet of BD203 Transistor :

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