Re: LMX2541 vs ADF4351


Richard <richard@...>
 



Thanks
a lot quicker and allows the ref doubler, so the phase comp is at 20 MHz 


Richard


On Sat, 2019-05-11 at 21:22 +0100, Andy G4JNT wrote:
Use my design tool
LMX2541_Prog.exe  contained in  http://g4jnt.com/LMX2541Support.zip

It can be used just to get the register values without having to use the RS232 interface.



On Sat, 11 May 2019 at 21:10, Richard <richard@...> wrote:
OK Andy
I just tried hard to get the ref divider down , but TI tool didn't want to play except with 2.5 and 2 MHz, I'll have another play and see if I can move the ref freq up
Richard


On Sat, 2019-05-11 at 21:03 +0100, Andy G4JNT wrote:
Close-in phase noise is purely a function of the reference.   Only when you get outside the loop bandwidth does the PLL chip come into the equation
In both you should be using Fcomp thd maximum you can - probably 10MHz, and a loop bandwidth in the 10 - 30kHz region


On Sat, 11 May 2019 at 20:56, Richard <richard@...> wrote:
Which in practice has the better close in phase noise
 Fvco =3321MHz, Fout =1660.5 Fref-10MHz  phase comp freq 2.5MHz
I'd forgotten I have quite a few that I got as samples, and one of
Andy's boards from a few moons ago
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 Richard Bown
 
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-- 
 Best wishes /73 
 Richard Bown
 
 Email : richard@...

 HTTP  :  http://www.g8jvm.com
 
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 Ham Call: G8JVM . QRV: 50-432 MHz + Microwave 
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 QRV 6mtrs 200W, 4mtrs 150W, 2mtrs 300W, 70cms 200W, 
Microwave 1296MHz 140W, 2320MHz 100W & 10368MHz 5W
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