Panson thanks for sharing this with the rest of the community.
Thanks for sharing!
The noise you got was 80KHz?
I am getting ~ 50Hz according to the oscilloscope
If you are getting power line noise your grounds to scope not right. The principle
noise seen in the Vdacout is relatively high (to 50 Hz) switching noise coupled
on chip and external by stray C.
Depending on what you are doing you may have to float scope ground. See attached.
Take a look at this discussion on power line interference -