please can some one help me how to use the referenca pin in this chip
,so what the effect of change refernce pin on the out put
http://www.alldatasheet.com/datasheet-pdf/pdf/48094/AD/AD622AR.html
thanks

 

If you read the data sheet on page 7, it states the output voltage is referenced to the REF pin potential (i.e. for 0V output the voltage between the output and REF is 0V). Thus for normal operation with a plus and minus supply, you connect the REF pin to circuit common.

Edit: If you connect REF pin so some voltage, then the output will referenced to (offset by) that voltage.