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AD5764 AGNDx pin internal connection

Question asked by Aion on Apr 10, 2012
Latest reply on Apr 11, 2012 by Aion

Hi,

 

After reading the AD5764 datasheet I am a bit confused.

 

What is the internal connection of an AD5764 AGNDx pin?

 

In Fig.1 it is shown, that these pins are connected with noninverting inputs of the output operational amplifiers.

If it is so, then the current flowing through an AGNDx pin should be small, constant, and equal to the bias current of the noninverting input of the output operational amplifier.

 

But in Fig.32 of this datasheet these pins are connected with the DAC switches. In this case the current flowing through an AGNDx pin is relatively high and depends on the DAC input code,

 

I think, that the Fig.1 is correct and the all DAC ladder/segment currents flow out of the REFGND pin instead of AGNDx. Am I right? If yes, what is the typical current flowing through an AGNDx pin?

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