I am using AD5941 in my design.AD5941 AVDD and DVDD are powered separateley using two regulators . Same LDO P/N is used.One for powering AVDD and the other for Powering DVDD.

In my board I have couple of other components also, one is a MUX, one buffer and one not gate. May I know can I power all these using the same DVDD which is powering the ADC

 

Yes, as long as the current requirements of the other components do not exceed the regulator's capability which should be stated in the datasheet. For example, 3.3 VDC @ 250 mA. What happens at the limit depends on the specific regulator. In some cases, the regulator will drop the output voltage and behave more like a constant power device. Other regulators might have a shutdown feature when the current limit is exceeded. It is essential to ALWAYS RTFDS.

 

LDO can provide 600mA.
AD5941 max current consumption is 25.2mA
One not gate 5uA
4 Mux will take total of 4uA
Buffer will take 1mA

 

That should be OK. If you will be doing a PCB layout, make sure all analog chips are connected to a ground going back to the regulator. Put all the other (non-analog) chips on a physically separate ground which meets up with the analog ground at the single point at the regulator chip. The idea is to make it more difficult for noise on the digital chips to go all the way back to the regulator and then out to the ADC.

 

Let me give a brief idea about my circuit.Below is the block diagram.The inputs are coming from an electrochemical sensor IC.It has 3 signal line called counter electrode(CE),Working electrode(WE) and Reference electrode(RE).From electrochemical sensor CE and WE will directly come to MUX ,RE is coming via buffer.All are working at 3.3V.I gave the the details of components already.

 

That should be OK. If you will be doing a PCB layout, make sure all analog chips are connected to a ground going back to the regulator. Put all the other (non-analog) chips on a physically separate ground which meets up with the analog ground at the single point at the regulator chip. The idea is to make it more difficult for noise on the digital chips to go all the way back to the regulator and then out to the ADC.

I am planning to use a single solid GND plane

 

I am planning to use a single solid GND plane

I don't remember telling you that a single ground plane was a good idea. You want sperate ground planes: one analog and one digital, tied together at a single point. But, hey you do you and don't bother complaining about the results

 

I don't remember telling you that a single ground plane was a good idea.

You never told me that.
If I am using AGND and DNGD we need to connect it at some point.Please correct me if I am wrong

 

You never told me that.
If I am using AGND and DNGD we need to connect it at some point.Please correct me if I am wrong

You do! You connect the two grounds at the ground pin of the regulator! Go back and carefully reread post #4