[sdiy] Buffered opamp used as a 2Mhz power amp...

[rburnett at richieburnett.co.uk]

* EVERYTHING THAT GORDON ALREADY SAID *  plus...

Take a look at current-feedback op-amps like the THS3001 for the driver, 
and Class-E power amplifiers using a single MOSFET like IRF510 or IRF520 
for the main power amplifier.  Class-E is a switching type power 
amplifier that can approach 100% efficiency when you are operating down 
in the single MHz frequencies.  They are used in the broadcast industry 
from a few watts up to large transmitters that radiate hundreds of 
kilowatts.

There's an example of a 500watt 4MHz RF power source on my webpage here 
(just leave off the final high-power PA):

http://www.richieburnett.co.uk/hfsstc.html

For some background take a look at the papers by Nathan and Alan Sokal 
and those by Raab and Rutledge at Caltech.

-Richie,





On 2014-08-20 15:05, gordonjcp at gjcp.net wrote:
> On Wed, Aug 20, 2014 at 09:59:05AM -0400, Jean-Pierre Desrochers wrote:
>> This is out of 'usual' topics for synth DIY forum but
>> some of you guys could have some clues about it..
>> 
>> I want to build a small power amp (5-10w @ +/- 15vdc) that
>> could drive a 50 ohms load with a fixed 2Mhz pure sine.
>> I'd like to use an opamp driving a push-pull stage (ex: using 
>> TIP29-30)
>> What type of opamp could be used at that frequency ?
>> The input level would be around 1vpp.
>> I was thinking of NE5532 as a frontend..
>> 
>> Thanks..
> 
> You're getting into the realms of power RF engineering.  Have a look
> at how power amps for the 160m and 80m amateur bands are constructed.