I am trying to understand the documentation here, regarding harmonics of DAC output. In particularly, I am interested in the phase relationship between the harmonics.

Based on figure 8 here,

http://www.analog.com/media/en/training-seminars/tutorials/MT-085.pdf

I have attempted to simulate a sample and hold DAC output but can't seem to replicate the noise floor nor the magnitude. Is there any additional documentation?

I have also attached my test code written in Matlab.

Thanks.

With a sample rate of 80MHz producing a tone that is 2MHz with 4096 points you won't be coherent. In other words you aren't producing a full cycle of a sine wave. Since the starting point and ending point are not the same the FFT will translate that into phase noise so you are seeing spreading around the fundamental:

If you change the desired frequency to a coherent frequency, so the full period of the sine wave is used you will see the noise floor you want to see.

The frequency I used for this test was f = 2.01171875e6;. I made this change on line 15 of your code.

If you are trying to simulate an ideal converter there won't be any harmonic distortion and the only noise will be quantization noise.