STMicroelectronics

BC847B

BC847B Description

The BC847B from STMicroelectronics is an NPN bipolar junction transistor (BJT) housed in a compact SOT-23 surface-mount package. Designed for general-purpose amplification and switching applications, it offers a collector-emitter breakdown voltage (Vceo) of 45V, a maximum collector current (Ic) of 100mA, and a transition frequency (ft) of 100MHz, making it suitable for low-power, high-frequency circuits. With a DC current gain (hFE) of 200 (min) @ 2mA, 5V, it ensures reliable signal amplification. The transistor is RoHS3 compliant, REACH unaffected, and features a low collector cutoff current (ICBO) of 100nA, enhancing efficiency in precision applications.

BC847B Features

• High Voltage Tolerance: 45V Vceo for robust performance in low-voltage circuits.
• Low Saturation Voltage: 500mV @ 5mA, 100mA, minimizing power loss in switching applications.
• High Transition Frequency: 100MHz enables use in RF and high-speed signal processing.
• Compact & Reliable: SOT-23 package with MSL1 (unlimited) moisture sensitivity, ideal for automated assembly.
• Low Leakage Current: 100nA ICBO ensures minimal power wastage.
• Wide hFE Range: Guaranteed hFE ≥ 200 for consistent amplification.

BC847B Applications

• Signal Amplification: Audio preamps, sensor interfaces, and low-noise analog circuits.
• Switching Circuits: Load drivers, relay control, and low-power DC-DC converters.
• High-Frequency Designs: RF stages, oscillator circuits, and communication modules.
• Portable Electronics: Battery-operated devices due to low saturation voltage and leakage.
• Automotive & Industrial: Non-critical control systems where 45V tolerance and SMT reliability are advantageous.

Conclusion of BC847B

The BC847B is a versatile NPN BJT offering a balance of voltage tolerance, switching speed, and amplification performance. Its low saturation voltage, high hFE, and 100MHz ft make it superior to generic transistors in precision and high-frequency applications. While now obsolete, it remains a reliable choice for legacy designs or replacements in consumer electronics, industrial controls, and RF systems. Engineers value its SOT-23 footprint and STMicroelectronics' quality assurance for space-constrained, high-efficiency designs.