V(br)CER

[ronv]

I'm building an RF amplifier and I came upon a new term that I don't know - V(br)CER. Collector to emitter breakdown voltage vs. base to emitter resistance. Does anyone know how to apply this term to the circuit below?
The transistor is a 2SC1971. It has a Vce of 17 volts, but this V(br)CER goes from 54 down to 22 volts depending on the base emitter resistance.

 

[crutschow]

It is simply the maximum collector-emitter voltage you can apply for various values of base-emitter resistance. Its value is between the maximum Vceo and maximum Vcbo (The o means the terminal not mentioned is open).

 

[ronv]

Spec.

Attached is the curve and the max rating specs. If I apply your explanation I have 50 ohms base to emitter (47+3.3) so I should be able to have the collector go as high as 50 volts? This would violate the collector emitter voltage of 35 volts so I should limit the output swing to say 25 or 30 volts (less than 35 volts).?
I like this cause I can get a lot more power out, but I want to make sure I have it right.

 

[crutschow]

For 50 ohms base-emitter resistance you could go to 40V on the collector to emitter before it breaks down, but that often causes a catastrophic failure. For best reliability you normally don't want to operate above about 75% of that value. And you never want to go above the Vcbo Absolute Maximum value of 35V.

 

[ronv]

Thanks for the help! Now it make sense that they could get 6 watts out of that transistor.