## Component Calcs for ClassE Single-Ended

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### Component Calcs for ClassE Single-Ended

If you don't use spreadsheets and use MatLab, here is a calc listing for a ClassE amp. If you don't have MatLab, you can use each step as a value for hand calculations, or use them in a spreadsheet. This listing includes FET output capacitance and the RDSon. In this calculation, Cshuntprime has to be greater than the FET output capacitance.

% Component Calcs for Switchmode RF Power Amp ClassE using an "L" harmonic filter
%
Coss = 300e-12
Rdson = 0.7
FH = 3.955e6
FL = 3.5e6
BW = FH - FL
Fc = 0.5*BW + FL
Q = Fc/BW
VDv = 100
Vsquared = VDv^2
Power = 350
POVDv = Power/VDv
pi = 355/113
Omega = 2*pi*Fc
Omegasquared = Omega^2
Cshuntprime = (0.212/OmegaR)
Cdrainshunt = Cshuntprime - Coss
CseriesTune = .685/(Omega*(QR - X))
LseriesResonant = 1/(Omegasquared*CseriesTune)
Lrfc = 50*RoverOmega % multiply by 0.283 for Push-Pull Operation with a center tapped output transformer
Vpeakdrain = 3.67*VDv
Isupplyavg = 1.1*POVDv
Idrainmax = 2.647*Isupplyavg
%

Computed values for 80 meters and a 350 Watt carrier were rounded up:

Fc = 3.728 Mhz
Q = 8.2
Power = 350 Watts
Cdrainshunt = 687 pF
CseriesTune = 453 pF
LseriesResonant = 4.0 uH
Lrfc = 20 uH
Vpeakdrain = 367 Volts
Isupplyavg = 3.9 Amps
Idrainmax = 10.2 Amps

Cheers - AC0OB
DMOD
Member

Posts: 22
Joined: Tue May 05, 2009 10:59 am

### Re: Component Calcs for ClassE Single-Ended

Also, you can check this URL. There are a number of good design tools there for class E.

Regards,

Steve
Visit the class E web site at: steve_qix
Class E Guru

Posts: 434
Joined: Fri Jan 31, 2003 11:03 am
Location: Townsend MA 