BC858B Transistor 3K PNP 30V 100mA 300mW SOT-23

BC858B Transistor 3K PNP 30V 100mA 300mW SOT-23 is a high-quality, surface-mount silicon epitaxial planar PNP transistor designed for general-purpose switching and amplification. This component features the compact SOT-23 package, making it an excellent choice for modern, high-density printed circuit boards where space remains at a premium. Furthermore, the BC858B offers low noise and low voltage characteristics, ensuring high fidelity in signal processing applications. Consequently, engineers frequently select this device for its reliability and consistent DC current gain. Therefore, you should consider this transistor for any low-power electronic design that requires efficient performance within a minimal footprint.

Key Features:

• SMD Compatibility: The SOT-23 surface-mount package facilitates automated assembly and reduces overall PCB size.
• Low Noise Figure: This transistor minimizes electrical noise during operation, making it suitable for sensitive audio and signal pre-amplification.
• High Gain Selection: The “B” suffix indicates a specific DC current gain range, providing predictable performance for circuit biasing.
• Robust Thermal Stability: It maintains stable operation across a wide temperature range, enhancing the longevity of the final product.
• Wide Voltage Range: Capable of handling up to 30V, it easily supports standard battery-operated and low-voltage rail systems.

Technical Specifications:

• Transistor Polarity: PNP
• Collector-Emitter Voltage (V_CEO): −30 V
• Collector-Base Voltage (V_CBO): −30 V
• Emitter-Base Voltage (V_EBO): −5 V
• Collector Current (I_C): −100 mA Continuous
• Total Power Dissipation (P_tot): 300 mW
• DC Current Gain (h_FE): 220 to 475 (B Classification)
• Transition Frequency (f_T): 100 MHz minimum

Mechanical Specifications:

• Package Type: SOT-23 (Small Outline Transistor)
• Lead Strain Relief: Integrated into the lead frame design
• Moisture Sensitivity Level: MSL 1 (Unlimited floor life)
• Marking Code: 3K (Typical for BC858B variants)

Dimensions:

• Package Length: ≈ 2.9 mm
• Package Width: ≈ 1.3 mm
• Total Height: ≈ 1.0 mm
• Lead Pitch: ≈ 1.9 mm
• Weight: ≈ 0.008 g

Pinout and Wiring:

• Pin 1 (Base): Controls the flow of current between the emitter and collector; require a small negative current to activate.
• Pin 2 (Emitter): Connect this to the positive supply rail in most PNP switching configurations.
• Pin 3 (Collector): Connect this to the load or the next stage of the circuit.
• Wiring Note: However, always ensure your PCB layout matches the SOT-23 footprint precisely to avoid alignment issues during reflow.

Datasheet Reference:

• Download Nexperia BC858 Series Datasheet

Commonly Used in:

• Handheld Devices: Ideal for smartphones, tablets, and wearables due to the small SOT-23 size.
• Automotive Electronics: Used in control modules and sensor interfaces where low power is required.
• Consumer Appliances: Found in control boards for washing machines, microwaves, and thermostat systems.

Applications:

• Signal Switching: Efficiently toggles low-current signals in digital and analog hybrid circuits.
• Audio Amplification: Serves as a pre-amplifier stage for microphones and small speakers.
• Current Mirrors: Utilized in integrated circuit design to create stable current references.

Equivalent Models:

• BC857B: A similar PNP transistor with slightly higher voltage ratings (45V).
• MMBT3906: A common general-purpose PNP SMD transistor with comparable current handling.
• BC558: The through-hole (TO-92) equivalent version for prototyping; however, it requires a different board layout.

Package Includes:

• 1 x BC858B Transistor 3K PNP 30V 100mA 300mW SOT-23