BC309 PNP Transistor Pinout Datasheet

Introduction

The BC309 is a low-noise PNP bipolar junction transistor (BJT) primarily designed for audio frequency amplification and low-level signal processing applications. It is widely recognized for its exceptional low noise figure, which makes it highly suitable for use in microphone preamplifiers, tone control circuits, and high-fidelity audio systems. The transistor provides excellent linearity and gain stability, ensuring superior sound clarity and minimal signal distortion in analog circuits.

Encapsulated in a TO-92 plastic package, the BC309 is compact, easy to mount, and compatible with most low-power circuit layouts. It features a maximum collector current of –100mA and a collector-emitter voltage of –20V, making it ideal for small signal and low voltage amplification. Its consistent gain performance and reliability under various temperature conditions make it a preferred choice for both commercial audio devices and DIY electronics projects.

BC309 PNP Transistor

The BC309 belongs to the BC307–BC309 transistor family, a series of PNP low-noise transistors with different voltage ratings and current gain (hFE) ranges. The BC309 is optimized for ultra-low noise operation, making it especially valuable in sensitive input stages of amplifiers or audio mixers. Its wide availability and reliable electrical characteristics ensure long-term use in educational kits, repair projects, and modern analog designs requiring clean signal amplification.

Pinout of BC309

Key Features

• PNP low-noise transistor for clean audio amplification
• Designed for low-frequency and small-signal amplifier circuits
• Compact TO-92 package for easy PCB integration
• Stable current gain across a wide temperature range
• Excellent linearity for low-distortion analog signal processing
• Suitable for high-fidelity and preamplifier applications

Specifications/Characteristics

• Collector–Emitter Voltage (VCEO): –20V
• Collector–Base Voltage (VCBO): –25V
• Emitter–Base Voltage (VEBO): –5V
• Collector Current (IC): –100mA
• Power Dissipation (Ptot): 500mW
• DC Current Gain (hFE): 110 to 800 (depending on group)
• Transition Frequency (fT): 120MHz typical
• Noise Figure: 1.5dB typical
• Junction Temperature Range: –55°C to +150°C
• Package Type: TO-92

Pin Configuration

Comparison Summary: BC307 vs BC308 vs BC309

• BC307 has the highest collector-emitter voltage rating (–45V), making it ideal for higher voltage circuits or preamplifier stages that require wide headroom.
• BC308 offers a moderate collector-emitter voltage (–25V) with a wide hFE range, providing balanced performance for general-purpose audio and analog amplification.
• BC309 has the lowest collector-emitter voltage rating (–20V) but provides the lowest noise figure, making it the best choice for high-sensitivity input and microphone preamplifier circuits where signal clarity is crucial.

More Circuit Layouts

Key Applications of BC309 PNP Transistor

• Audio preamplifiers and low-level signal amplifiers
• Microphone and tone control circuits
• Low-distortion amplifier input stages
• Small-signal general-purpose switching
• Analog and instrumentation amplifiers
• DIY and educational low-noise electronic projects

NPN Complimentary Transistor

• The NPN complementary transistor of BC309 is BC549.
  This complementary pair (BC309 & BC549) is commonly used in push-pull amplifier stages and class AB audio configurations, providing balanced and distortion-free signal amplification across both positive and negative cycles.

Equivalent Transistors of of BC309 PNP Transistor

• BC307
• BC308
• BC556
• BC557
• BC558
• 2N2907
• 2N3906
• S8550

(Pin configuration of some transistors mentioned here may different from BC309).

Datasheet of BC308 PNP Transistor

Click the following Button below to download the datasheet of BC309 Transistor :

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