Thanks for the reply,
I will give you in detail what i am trying to do ,
Depending on the 3phase input voltage my input at ADC should vary .For example if my 3 phase input is 400v then input at ADC should be 3v,if input is 200v then adc input should be 2v .
For doing this i stepped down the voltage to 3v using voltage divider and converted to 3v DC ,after converting to dc can i give this directly to ADC of controller ,or i should use linear optocoupler,if linear optocoupler is to be used then which is the best one(cost effective).please suggest me with the complete design.
Thanks for your reply