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Separating AGND and DGND at the ADC/ DAC

Question asked by apomerants on Dec 23, 2012
Latest reply on Jan 10, 2013 by jcolao


I am using in my design the AD7656 and the AD5724.

At the AD7656 I saw a specific recommendation to use separate Ground planes for AGND pins and for DGND pins and to connect them with a resistor (under the chip itself).

However, in the Analog-Devices MT-031 app note, which examine this very issue, it states doing such a separation is a "disaster" !!

This app note demands both AGND and DGND pins to be connected to the same AGND plane.


Which concept should I follow?



Can it be that the MT-031 app note is not relevant for SAR ADC such as the AD7656?




Amnon Pomerants