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How to design a 50MHz power amplfier

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vdaniel

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Though I am enough experienced with different kinds of Electronics Design, the
RF is completely new for me.
I need to design a 50 MHz amplifier, working on a 50 Ohm load, with output power in range of 20...50 W. Please, recommend how to start, any references, etc.
Thanks,

Varuzhan
 

Re: 50MHz Power Amplfier

Please clarify the following:
gain
supply voltage
and, the most important, should it be linear or C/D class will be OK?
Regards,
IanP
 

Re: 50MHz Power Amplfier

It does not to be linear, I think C/D class is enough. Supply voltage 24V or 12V.
As an input I want to use a standard 50MHz quartz oscillator, for example Epson GS-8002.

Varuzhan
 

Re: 50MHz Power Amplfier

Attached is a diagram of wideband D-class amplifier which can be driven of TTL levels.
Supply can be 24 for power stage and 12V for pre-amplifier.
If you like this concept I can give you more details on this circuit.
Regards,
IanP
 

Re: 50MHz Power Amplfier

Dear IanP.

Thank you. It is just what I need for the beginning. Sure I need more information about active (transistors and diodes) and passive (L and C) components.

Best regards,
Varuzhan
 

Re: 50MHz Power Amplfier

Here is the list of transistors:
npn:
http://www.fairchildsemi.com/ds/2N/2N3904.pdf
npn--pnp:
**broken link removed**
**broken link removed**
power npn:
**broken link removed**
Diode = 1N4148 or similar
1st toroidal:
primary=5
Secondary=2 x 2
2nd toroidal:
primary(s)=2 x 4
secondary=4
You will have to experiment with the type of toroidal cores used in wideband transformers applications, have a look in here:
**broken link removed**..
Regards,
IanP
 

    V

    vdaniel

    Points: 2
    Helpful Answer Positive Rating
Re: 50MHz Power Amplfier

Dear IanP.

Please can you describe the cores material, shape and dimension.
Thank you in advance,
Varuzhan
 

Re: 50MHz Power Amplfier

Hier is info on toroidal cores:
Small core:
**broken link removed**
Big core:
**broken link removed**
Attached picture: 20MHz fm amplifier.
Regards,
IanP
 

Re: 50MHz Power Amplfier

Dear IanP,

Thank you very much, but 20 MHz is not 50 MHz. Are you sure, that the same cores
will work good for 50 MHz?

Varuzhan
 

Re: 50MHz Power Amplfier

I can't be sure, but according to this (from Farnell):
CORE, 5.0MM; Diameter, external: 9.65mm; Diameter, internal: 5.0mm; Impedance, typical @ 100 MHz: 43R; Impedance, typical @ 25 MHz: 26R; Length / Height, external: 5.05mm; Material, case: 4S2
Click to expand...
they look like they should cope with 50MHz.
As I mentioned previously, you will need to experiment a little bit ..
Regards,
IanP
 

    V

    vdaniel

    Points: 2
    Helpful Answer Positive Rating
Re: 50MHz Power Amplfier

Ok, thank you very much.
And can anybody recommend an ebook about this stuff, which could be dowloader from this forum or other site.
Thanks,

Varuzhan
 

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