Post Go back to editing

AD9117 NSD measurement setup

Category: Datasheet/Specs
Product Number: AD9117

Hi all,

i want to use the AD9117 to generate a very low phase noise, amplitude modulated signal at 37.5 MHz. I drive the DAC with an appropriate low phase noise (<155dBc/Hz @ 1MHz) 100MHz source want to achieve similar performance out of the dac,

preferably <150dBc/Hz @ 1MHz.

The datasheet gives different specifications for the output noise. First one says 37 pa/sqrt(Hz) which works out to ~164 dBm/Hz in my application. Now looking at the plots for the NSD at different frequency the AD9117s noise is very dependent on output frequency even

when taking into account sinc rolloff, while the AD9114s noise doesnt really veer off the expected level of ~132 dBm/Hz calculated from the 1471 pa/sqrt(Hz) datasheet spec.

A different part, the AD9106 shows almost no correlation between output noise and frequency and seems to perfrom much better over it frequency range while having a nominal resolution of only 12 Bits. 

Looking into the AN-928 Understanding High Speed DAC Testing and Evaluation, all three signal sources used to measure NSD have a phase noise no lower than -150 dBc/Hz @ 1MHz.

My question now is, was there a difference between the sources used to measure NSD for the AD9117 and AD9106?

How could i estimate the phase noise contribution of the dac itself?

Thanks alot in advance!



Clarification and typos
[edited by: dinocroc123 at 6:57 PM (GMT -4) on 10 Aug 2024]