Questions about Sigma delta ADC (resolution)

[kkokkogom]

sigma delta adc resolution relation

Hi,
for sensor application, I've to design a 12bit(minimum) Sigma delta ADC.
I have some questions..

I guess lots of sigma delta modulators are using a fully differential opamp for integrator.
Do I have to use fully differential opamp for 12 bit resolution?
I focus on low power and low voltage ( vdd = 1V) ,
so I think fully diff-opamp doesn't fit..


How many order do I need? ( how about 3rd order & single bit?)
Do I have to use Fully differential opamp?

plz help me[/quote]

 

[JoannesPaulus]

how to calculate resolution of adc

Do I have to use fully differential opamp for 12 bit resolution?

You should.

I focus on low power and low voltage ( vdd = 1V), so I think fully diff-opamp doesn't fit...

You have a pretty good chance to do it with a folded cascode op-amp (depending on your technology).

How many order do I need? ( how about 3rd order & single bit?)

There are plenty of books and papers that tell you how to calculate the order of a delta-sigma adc and - since you are asking this question - you should read a few of them before starting your design...