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AD7656 reference error question

Question asked by Lionelwallace Employee on Jan 16, 2014
Latest reply on Apr 6, 2014 by mrphilmo

This is an odd question.

 

I have a customer that designed a board using the AD7656-1.  His proto boards were accidentally populated with the AD7656.  He understands that he has insufficient decoupling.  However, so far, the A/D seems to be functioning properly with one problem.  The reference voltage is wrong.  It is at 2.27V not the expected 2.5V.  On the scope, the reference is very clean, but is not at the correct level.  The reference is lightly loaded.

 

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Could this error be a result of the insufficient decoupling that will be remedied when the ADA7656-1 is installed on the next set of boards OR do you think there is something else causing this reference error?

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