BC640

Overview

The Fairchild Semiconductor BC640 is a PNP silicon planar epitaxial transistor housed in a TO-92 plastic package. It is designed for medium power applications with a continuous collector current rating of 1 A and a collector-emitter voltage of 80 V. The device features a minimum DC current gain (hFE) of 63, ensuring reliable amplification and switching performance. Thermal resistance from junction to case is specified at 200 °C/W, while junction-to-ambient resistance in free air is 625 °C/W. The maximum operating junction temperature reaches 150 °C.

Feature Summary

• PNP medium power transistor configuration
• High current capability up to 1 A
• Robust voltage handling at 80 V
• Lead-free compliant construction

Applications

• General-purpose amplification circuits
• Switching applications requiring moderate power
• Audio output stages
• Driver circuits for loads

Procurement Notes

Verify the manufacturer marking matches Fairchild Semiconductor specifications. Confirm the package type is TO-92 and the pinout corresponds to standard Emitter-Base-Collector or Collector-Base-Emitter configurations as defined in the official datasheet. Ensure the component is lead-free if environmental compliance is required. Cross-reference part numbers with NXP equivalents if sourcing from alternative distributors.

Selection Notes

Select this component for designs requiring a robust PNP transistor with high current handling. The 80 V breakdown voltage suits general low-voltage logic and analog interfaces. Consider thermal management due to the TO-92 package limitations. Compare against similar NPN counterparts like the BC639 if complementary symmetry is needed. Verify hFE bins match circuit gain requirements.

Part Context

The BC640 belongs to a family of medium power transistors often paired with NPN types like the BC639. Manufactured by Fairchild Semiconductor, it utilizes silicon planar epitaxial technology. The TO-92 package provides a compact solution for through-hole mounting. It serves as a standard discrete semiconductor component for general electronic applications.

Replacement Considerations

The BC640,112 manufactured by NXP is a direct equivalent. Other compatible PNP transistors include the BC640A/B variants with different gain ranges. Verify pinout compatibility before substitution.