Re: RF power chain mods and improvements..


Howard Fidel
 

Allison
You are absolutely correct. I simulated it is LT Spice. I did not look close enough at the results. The drive current needed into the IRF510 is 220 ma peak at 30 MHz. The opamp is only good for 80. I need to add a current buffer to each opamp output.

Howard

On 6/9/2018 5:18 PM, ajparent1/KB1GMX wrote:
Hint the ADA4895 will not drive the IRF510s to full power.  It cannot produce enough power.

The PHA22 at 1DB compression is 22dbm almost 160mW  add IRF510 (assume low 13db gain)
and you get to almost 3.2W (if high maybe 6W).  The PHA22 is really power hungry and
regulated voltage.  If the board layout and pad are not right they can take off or melt.  Most
mmics trade power in for bandwidth. 


Allison


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