I have a question regarding the linearity of the AD9252. I am using a system that contains 32 ADC channels using the 4 off AD9252 devices. I find that I obtain the data sheet figures for INL if I drive only a single input channel of the AD9252. However if I drive all eight channels concurrently from the same source I obtain INL figures 2.5x worse than the data sheet worst case. I am wondering if anyone has come across this or if you have any good advice for me?
Does anybody know if this is a 'feature' of the part and would recommend changing the part for the AD9257-65 (I believe I can accommodate the small changes in device pin out)
The attachment has a couple of linearity plots and some circuit fragments that may be helpful.
I sincerely apologize for the delayed response.
I have not personally seen the degraded INL you mention and don't have a explanation yet. I'm looking futher into this.
Again, I'm sorry for the late response.
Thank you for taking some time to look into this.
If you require any further information about the actual hardware, the test setup and the processing to obtain the INL please don’t hesitate to contact me.
A piece of further information - a colleague of mine has independently tested our system using an entirely different test method and has obtained very similar results so I am happy that I have not made any basic errors in obtaining the INL data.