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Question on using internal reference of AD7682

Question asked by richiechen on Jan 29, 2013
Latest reply on Jan 30, 2013 by KarenNE

Dear Analog Technical Support Team


I have met a question on using internal voltage reference of AD7682.

I am using AD7682 as a voltage reference at the same time. It is designed to shift up ac signals.


As is stated in the datasheet: "Because the current output of REFIN is limited, it can be used as a source if followed by a suitable buffer, such as the AD8605." I misunderstood that REFIN will be the voltage reference of 2.5V/4.096V.

But after doing some tests, I found that REF is exporting the voltage of 2.5V/4.096V....


My question is, is REFIN able to export stable voltage of 2.3V? Can I use it as a voltage shifter source with some resistors?


Because the PCBs have been made already to use 4.096V*1.1kOhm/4.4kOhm to provide 1V, it is easier to just change the resistors and export 1V from 2.3V.


I am in a very hurry condition..It would be really appreciated if you could help. (The attachment is my schematic. )

Thank you very much.




Richie CHEN