As i need not tell you, i will avoid the noise very much. I am familier with 24bit delta/sigma ad7710, ads1242, cs5502 ics But not able to get more than 1 in 100000.

Hallo Nagarajan,

if noise is your problem, you could try the technique of figure 18 of

http://www.linear.com/pdf/an61.pdf

By the way, do you use any sort of low pass filtering, when using delta/sigma converters? Can reduce noise very effectively!

Kai