BC549B

Single Bipolar Transistors Overview

The BC549BTA is an NPN epitaxial silicon transistor from the BC546–BC550 series, manufactured by onsemi. It features a collector-emitter voltage (VCEO) of 30 V and a collector-base voltage (VCBO) of 30 V. The device supports a maximum DC collector current (IC) of 100 mA and a power dissipation (PC) of 500 mW. Classified as 'B' gain, its DC current gain (hFE) ranges from 200 to 450 at IC = 2 mA and VCE = 5 V. The BC549B is specifically designed for low-noise applications, with a noise figure between 1.2 dB and 4.0 dB. It utilizes a TO-92 package.

Single Bipolar Transistors Feature Summary

• Designed for low-noise amplifier and switching applications
• NPN epitaxial silicon construction
• Complements the BC556 through BC560 PNP transistor series

Single Bipolar Transistors Applications

• Low-noise audio amplification stages
• General-purpose signal switching circuits
• Small-signal amplifier designs

Single Bipolar Transistors Procurement Notes

Verify that the ordering suffix matches the required packing method, such as Ammo or Tape and Reel, as indicated in the official datasheet. Confirm compliance with RoHS directives and lead-free manufacturing standards. Ensure the selected part number aligns with the specific hFE gain classification required for the circuit design.

Single Bipolar Transistors Selection Notes

Select this component when low-noise performance is critical for small-signal processing. The B-class gain band provides a moderate amplification range suitable for general-purpose tasks. Consider the complementary BC559B for matched PNP/NPN configurations in push-pull or differential amplifier topologies.

Single Bipolar Transistors Part Context

This device belongs to the BC546 through BC550 family of NPN transistors. While sharing identical electrical ratings for voltage and current, the BC549 variant is distinguished by its optimized low-noise characteristics compared to the standard BC547 or BC548 models.

Single Bipolar Transistors Replacement Considerations

• BC549BTF
• BC549CTA

Single Bipolar Transistors FAQ

What distinguishes the BC549B from other members of the BC54x series?

The BC549B is specifically characterized as a low-noise transistor, featuring a lower noise figure compared to the standard BC547 or BC548 variants within the same series.

How does the Fairchild integration affect the part numbering?

Underscores in original Fairchild part numbers are replaced with dashes to meet ON Semiconductor system requirements; however, the functional specifications remain unchanged.