Sunday, 4 March 2012


I have the MRFE6VP6300H in the AR305 circuit now.
I have had to change the input transformer from a 9:1
to a 4:1 and add some inductance to both the input and

The amplifier oscillates at about 230 MHz and the only
way I can stop the oscillation is by placing a capacitor
across the output of the dual FET. This is not optimum.

So far I am getting about 150 watts out with around 27db
of gain at 70 MHz with a power supply of 48 volts and
drawing 6 amps, the device is biased on at 2 amps.

The input match appears quite good but the output match
is lousy. I would probably have been better off starting
with a fresh design and doing away with the ferrite loaded
output transformer which gets very hot (yes I managed to
burn my finger on it by accident). Still these Freescale
devices look to be the bees knees for modern amplifiers
up to 600 MHz.

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