ADF4351 Output power


geoffrey pike
 

Last night i discovered that all of my ADF4351 boards have their outputs returned to supply volts via a 50R resistor, i suppose to make one size fit all needs and if you want you can change it.
Not having anything other than a 47nH 0603 inductor i tried this instead of the 50R resistor and well :-
with 50R
106.5 MHz = 1.25 mW
432 MHz = 1.35 mW
1242 MHz= 1.30 mW
2500 MHz= 4.0 mW

with 47nH
106.5 MHz = 3.6 mW
432 MHz= 4.6 mW
1242 MHz=3.8 mW
2500 MHz =4.1 mW

This achieved a 4.6 dB increase where i wanted it at 1242 MHz, no doubt a balun would give even more but the single resistor change was a quicky just to see, not sure if the above table is going to come out correctly
cheers
Geoff
GI0GDP


militaryoperator
 

On my boards Geoff the o/p go through a 1nf then there's a 3.9nh up to a 3v rail from the chip pin. 

I have the little boards with the small screen and 5 buttons on them. 

Ben G4BXD


Subject: [UKMicrowaves] ADF4351 Output power

Last night i discovered that all of my ADF4351 boards have their outputs returned to supply volts via a 50R resistor, i suppose to make one size fit all needs and if you want you can change it.
Not having anything other than a 47nH 0603 inductor i tried this instead of the 50R resistor and well :-
with 50R
106.5 MHz = 1.25 mW
432 MHz = 1.35 mW
1242 MHz= 1.30 mW
2500 MHz= 4.0 mW

with 47nH
106.5 MHz = 3.6 mW
432 MHz= 4.6 mW
1242 MHz=3.8 mW
2500 MHz =4.1 mW

This achieved a 4.6 dB increase where i wanted it at 1242 MHz, no doubt a balun would give even more but the single resistor change was a quicky just to see, not sure if the above table is going to come out correctly
cheers
Geoff
GI0GDP