AnsweredAssumed Answered

AD719X Ref1 vs Ref2

Question asked by olso4539 on Sep 24, 2012
Latest reply on Sep 25, 2012 by MaryMc

I was originally unaware that there was a fundamental difference between Ref1 and Ref2 on the AD719X family.  Now that i look again at the diagram

Functional Block Diagram for AD7193

I see that there is a difference.  Does this have any effect on the accuracy of conversion or the specifications on the data sheet?  Are there any consequences to using Ref2?

 

I am in an application where i would like to use Ref2 with conversions on Ch0 and Ref1 with conversions on Ch3.  Is there any consequence to having a different reference voltage applied to each set of pins?  Are the two internally connected when Ref2 is enabled?  That would cause an unintended current flow and error in my particular application.

 

In another forum post it was mentioned that Ref1 should be used with the temperature sensor.  From the look of the diagram it seems as though the temp sensor should function the same as any of the input channels when Ref1 or Ref2 are used.  There is also nothing in the data sheet that suggests that Ref1 must be used for the temperature sensor.  Where is the excitation current for the temperature sensor coming from?  The reference pins or AVdd? Should i then be using AVdd as my reference for temperature conversions instead of a remote sense connection to my external sensor on Ch0 or Ch3?

I apologize for all the questions.

-Jon

Outcomes