need DNW for capacitor in ADC?

[iexplorer]

noise isoltion dnw p+

Need I use some DNW to isolation capacitor to avoid noise ? I use MIM cap ,I thought that the caps are really far from sub,but I saw a lot of people use M1-Pactive to isolate ,why?

 

[leo_o2]

I think DNW will have better substrate noise isolation than P+ active.

 

[iexplorer]

but how does it affect MIM cap?

 

[leo_o2]

It is influenced by cap coupling.

 

[Fady Atef]

I think DNW will have better substrate noise isolation than P+ active.

But DNW meaning that he will use additional mask , and this is not an option at all cases , so in my opinion the use of DNW or P+active will depends on the application