Re: Chinese ADF4351 signal source


G0FCU
 

Robin,

I have no experience of reading SMD component values so looking on Google it seems my R7 (code 74B) is 5.76k ohms and R9 (code 810) is 680R (see attached picture).

Calculating the value of Rset using 5.76k gives a value of Icp of 4.427mA. Reading the datasheet I should set the charge pump current registers to '1101' for Icp=4.38mA.
Having done this I can still get lock from 35 MHz to 4400 MHz and I have corrected a bug in F1CJN's sketch that meant that the lock status was not being updated correctly on the LCD.

73
Simon.


On Mon, 4 Jan 2021 at 16:19, Robin Szemeti - G1YFG <robin@...> wrote:
I just went to the shack to actually check mine ... I was guess at the 5K1 from memory

Mine has 680R for R9 just like the Chinese diagram, I think most of the "normal" software is set up for 1K0 ... it is marked here on the upper row, second one in.


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