[Amps] Advanced Power Technologies ARF1505

[Steve Thompson]

Peter Chadwick wrote:
> 
> Steve said
> 
>  >The 5400pF is measured at 1MHz, but it's not going to change that much
> at other frequencies, and at the upper end of hf Zi looks like a half
> decent short circuit. Maybe matching at the top end and then frequency
> tailoring an input attenuator will work.<
> 
> I make the input impedance of the order of -j0.9 at 30MHz. To get the 
> power, I reckon the drain to drain load is around 50 ohms, and that 
> means quite a few amps of drain current. Even if gm was 1A/V, that's a 
> fair amount of RF base current, and probable loss in the input matching 
> network.

The datasheet says +j0.6 at 27MHz - looking at the figures for 
13/27/40MHz, Zi models roughly as 9nH in series with 5400pF in series 
with 0.3R. The inductance sounds about right for the bond wires.

On the output side, resistive part of Zl is down to 5 ohms at 27MHz in 
order to pull 750W out (46 ohms at 2MHz).

As to your other questions - pass for now. I'd certainly want a 
plentiful supply of devices to start trying grounded gate.

Steve