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anti backlash for PLL

Question asked by sss on Aug 6, 2014
Latest reply on Aug 7, 2014 by Brigid.Duggan

Hi,

 

I'm confused on the setting of the BACKLASH to the PLL.

I have a question, about the anti-backlash value to PLL.

 

Checking some datasheets, "AN-873" and other discussion,

as following I understand setting the ABP value,

recommended or fixed value,

Fract-N PLL:wide pulse(e.g. 6ns )

Int PLL:narrow pulse(e.g. 3ns)

 

However, for each device,  there is a difference of selectable values or fixed value.

 

For example,

ADF4360-x(Int PLL) is selectable ABP values,

1.3,3.0,6.0ns.

ADF415x(Fract-N) is fixed 3.0ns >>> not wide pulse?

 

Can i set,select any values without restriction?

I do not think so!

I want to know whether which value of setting is correct.

 

What is correct choice values ??and calculation method  for BACKLASH?

And, which is important parameters to select a ABP value?

Fract-N PLL or Int PLL?

PFD?

others?

 

Thanks

Regard,

sss

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