The AD9516 system PLL (IC9) suffers from phase noise in the 8-10 kHz range. This noise is different on each reboot/restart of the system.

Measured using the U.FL connector (j5 or j6) and the phase noise analyser. The phase noise typically observed on the 125 MHz WR reference clock is ~2 ps RMS jitter from 10 Hz to 5 MHz. However, its performance can degrade significantly and may exhibit noise up to 10 ps RMS jitter.

To remedy this situation, it is proposed that we replace the AD9516 with an LTC6950.

It should also be noted that version 2 of this FMC-DAC-600m-12b-1cha-dds also suffered from this issue.