Re: ADF5355 - Good Enough for 24 GHz!


Andy G4JNT
 

Was just about to post a query,   then this message appeared.

Ref [3] in the Scatterpoint article , the circuit of the black board, points to a URL that requires a login or sign up.  WHich I'm not prepared to do.

In the article you just refer to bypassing the regulator with 3300uF low ESR.   By that, I assume the 5V regulator, it doesn't specifically say so.

Andy  G4JNT



Virus-free. www.avg.com

On 22 December 2017 at 11:26, Brian Flynn brian.flynn@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

I echo the sentiment that the ADF5355 (or the ADF4351) should be run at
high charge pump current levels to keep the close to carrier PN down. I
have also found that the highest possible PD frequency helps. Certainly
going from 25 to 50 MHz helps noticeably. The improvement going to 100
MHz was not so obvious. The effect of varying other parameters was not
discernible.

I have expanded on the Scatterpoint article and and added some more
plots which may be of interest.

https://gm8bjf.joomla.com/past-talks/15-reducing-phase-noise-pn-on-chinese-adf5355-boards

I have also put links to the schematics of the "black" PCBs. (Found on
various Chinese websites)

73s
Brian Flynn
GM8BJF


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