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AD9958 PLL parameters and discrepancy between datasheet and Eval Board Schematic.

Question asked by Dorin on Sep 30, 2015
Latest reply on Jan 12, 2016 by Dorin

Hi all,

I noticed that the AD9958 datasheet recommends a loop filter with R=0, C=680pF tied to AVDD.

The Evaluation Board schematic shows R=680ohm, C=680pF tied to GND

(Eval board values seem to be correct as an R = 0ohm would result in severely under-damped loop characteristic).

Which values would be correct?

 

or a better question:

What is the PLL's VCO sensitivity in MHz/V?

(This value should change with frequency and a chart or tabulated data would be needed).

 

It would be nice if ADI would integrate the AD9958 PLL parameters into the ADIsimPLL for simulation.

 

Regards,

Dorin PhD

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