BC549 Transistor - Plastic Package TO-92

BC549 Transistor 

The BC549C is an NPN transistor belonging to a group of general-purpose NPN semiconductors consisting of BC547, BC548, and BC549. These transistors are utilised in audio frequency, and small signal directly coupled preamplifiers.

The general-purpose range of transistors is a good substitute for basic non-critical audio applications, as these transistors are similar and equivalents to each other.

These transistors are the direct modern equivalent replacements to the earlier BC107, BC108, and BC109. The most noticeable difference is in the packaging and pin configuration. The BC109 package was TO-18 / SOT18 metal canister, whilst the modern BC549 package is a TO-92 / SOT54 plastic material.

The BC549 is an NPN transistor; however, it also has a complimentary PNP version, which is the BC559.The complimentary version has identical characteristics except it is a PNP type. This is very useful for building symmetrical push-pull preamplifier stages.

Specifications:

• Breakdown voltage, collector-to-emitter with base open-circuit VCEO = 30 V (see below)
  
• Rated continuous collector current IC = 100 mA (Fairchild's BC548 at one time had a higher rating)
  
• Rated total power dissipation Ptotal = 500 mW (some manufacturers may specify 625 mW - see below)
  
• Transition frequency (gain-bandwidth product) ft = 150 MHz minimum (300 MHz typical)