ADF4002 antialiasing filter
Currently installed anti-alising filter (RC filter, 10kHz BW) cannot
operate correctly since ADF4002's CP pin is a current source.
A new proposed filter is attached in this issue with an AC SPICE simulation.
An inductor with self-resonance above 60MHz and DCR less than 500mOhms is suggested (e.g. http://uk.farnell.com/taiyo-yuden/brl3225t100k/wirewound-inductor-10uh-900ma/dp/1839390). Self-resonance should be at least 3 times the PFD working frequency.
A DDS board with these changes has already been successfully tested.