F5 power amplifier

[Nelson Pass]

I am confident that 5W resistors will be fine.

[Danger Mouse]

Originally Posted by Nelson Pass

This requires a little calculation:

The rated junction temperature of the Mosfets is 150C

The thermal resistance of the junction to case is 0.69 deg/watt

The case temperature + thermal resistance * watts cannot exceed 150C

So Watts * .69 < 95C, and Watts < 137 for the case temp = 55C

This of course is the absolute maximum. The rule of thumb is that every
10C reduction in junction temperature doubles the life of the transistor.

And how long is the lifetime for eample irfp240 at 55C?
Whats your experienced data?

Then I know for how long i have fun with my amps

[j.leger]

I have no data. But if it melts down next week you will be lucky. Then you get to build another one. Haha!

[Danger Mouse]

This will be really pity. I really love my F5 hopefully it runs forever.

This is why i`m asked. So i can estimate whether my amp will manage it.
Or i have to buy some toshiba spares for output.

[Nelson Pass]

Originally Posted by Danger Mouse

And how long is the lifetime for eample irfp240 at 55C? Whats your experienced data?

I run them in production at 55 on the sinks. This translates to maybe
65-70 case. They seem to run forever.

[Danger Mouse]

Many thanks for info

seems that i will be a lucky guy for a looong time

[tfender]

F5 For me
[IMG][/IMG]

[jacco vermeulen]

F5, the Pink Edition.
(what next)

[MEGA-amp]

1.8A, 25V, 10mV DC offset, no temp compensation, no current limiting, bias is rock solid. Planning on turning up the bias until something breaks.

[JBdV]

cool!