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ADALM2000 Analog/Digital grounds

In looking through the schematics for the ADALM2000 I noticed there are no separate Analog and Digital grounds and was wondering why?  I do see a separate PGND that runs through a common mode filter.  I am asking this question to better understand mixed mode system design, the applications notes that show separate Analog/Digital grounds ties at the ADC and the design of the ADALM2000 which does not bother with separate grounds.

Thanks in advance, Bill

  • Unless there is true galvanic isolation between the Analog and Digital sections of a system (either optical or magnetic isolation) there can really only be one common reference node or ground. In larger systems each section would have a separate connection back to a common point (so called star connection) to manage how the current returns and the unavoidable voltage drops that are produced. The M2k and other small data acquisition boards like this are too small to make this a thing. Any voltage drops in the power and ground planes are dealt with in the design of the layout.

    Doug