I am trying to understand how to separate the analog and digital grounds of an ADE7758-based design. The datasheet states that they should be connected together at one point, which is clear enough. What confuses me is the recommendation to place the current-sensing circuit on the digital ground (see AN-639, page 5):
Every circuit which I've looked into places the current-sensing circuit on the analog ground while maintaining separate digital and analog planes, for example AN-641 (A 3-Phase Power Meter Based on the ADE7752).
Can someone clarify which parts of the circuit should be placed on the digital and which parts should be placed on the analog plane?
The current sensing must grounded in the analog ground as this goes to the analog to digital conversion.
Those in digital ground must the grounds that corresponds to logic pins, SPI, communications, and clock.