[Amps] Class D RF amplifier

[John T. M. Lyles]

Speaking of QEX, in the spring issue, I think it was March/April, 
there was an article by "Fritz" Raab on a complementary MOSFET class 
D RF amplifier for 80 meters. The IRF610 N channel device is still 
around, but the Supertex p channel device is obsolete. I researched 
and found several viable complementary devices which can be tried in 
this circuit. Nothing with Vdd above 250 VDC. Contact me if you try 
to build this, and want to use current generation parts. The upper 
FET in the circuit diagram is shown reversed, actually the two drains 
need to be connected in common at the output, not as shown in the 
article.

This is a very cool amplifier in that it has no output or input 
transformer, just capacitive coupling. Efficiency is high, and of 
course, it is nonlinear, so that it would need to be used CW, AM with 
a modulator, or in an Envelope Elimination and Restoration amplifier 
configuration.

73
John
K5PRO