My customer is using AD9516 with the clock buffer of TI as shown below(refer to attached datasheet).
She said that if 10MHz input of clock buffer was connected directly to REFIN of AD9516, there was no problem and when she checked clock performance on output of clock buffer, there was no problem also.
But she had a problem that when REFIN of AD9516 was connected via the clock buffer, phase noise of AD9516 ouput was degraded.
Please advice the causes and solutions to the problem.
Thanks in advance.
I don't think there is enough information to diagnose the problem here. Any elements injected into the signal chain will degrade the phase noise performance some. If the AD9516-1 is multiplying the frequency up (I assume it is), then the noise added from the buffer inside the AD9516's loop bandwidth will also be multiplied up; the higher the multiplication factor, the more the noise is magnified.