Question:
What was the phase noise profile of the signal source used for the DAC clock when the characterization work for the data sheet was done?
Resolution:
We used a combination of the Rohde and Shwarz SMA100 (less than 1 MHz offset) and the Agilent PSA (greater than 1 MHz offset) signal generators for the data sheet plots. The plots are a composite curve using the best part of both signal sources. I think our recent article in Analog Dialogue is a better explanation of what we see as the noise contributions.
For information on improved phase noise performance and contributors to phase noise, please check this article in Analog Dialogue. http://www.analog.com/en/analog-dialogue/articles/analyzing-and-managing-the-impact-of-supply-noise-and-clock-jitter-on-high-speed-dac-phase-noise.html