I want to use the AD9525 as clock distribution (and PLL) for the AD9914. Therefor I'm looking for a (about 100-500MHz) refetence oszillatr for the AD9525.
The clock will be at 3.5GHz. I've seen, that the AD9525 has 2 differential ref-inputs and 1 single ended (ref c) input.
Now my questions are:
What is the difference between these inputtypes?
what is the advantage of a dif input?
Is there a difference (when using a single ended oszillator) in performance if i use the ref c input or the ref a input and couple the unused pin to ground (as discribed in the manual)?
This is because i watched for some oszillators at digikey.com. The point is, that there are dif output oszillators ( for example a LVPEC VCO), but they have a freq. stability of +-20ppm, where as single ended OCXOs have a stabilities of +-5ppm. Also the phasenoise is less.
Now the next question is:
would it be better to use a very stable single ended OCXO, or a dif output VCO to get the best possible performance of the ad9525 (also having in mind, that this should be a masterclock for te ad9914 DDS driver)?