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Original question:

XTR305: Loop Powered Example

XTR305: GND confusions about XTR305

Lucas Ding
Prodigy 320 points
Part Number: XTR305

Dear Team,

How about these GND1, 2, 3, 4 means... Does there any differences, and if there needs any isolation on this?

Thanks.


  • 0
    TI__Genius 12100 points
    Hi Lucas,
    It appears that each ground was numbered (similarly to how different resistors or capacitors would be numbered), but all should connect to the same ground net.
  • 0
    Guru 140200 points
    Hi Lucas,

    I think this shall indicate that the XTR305 can tolerate some common mode noise between these grounds.

    In section 6.5 you will find the entry:

    "Rejection of voltage difference between GND1 and GND2, RTO -> 130dB"

    Also figure 35 and 36 demonstrate that GND1 and GND2 need not necessarily to be identical.

    That GND2 and GND3 need not to be identical with GND1 (and with each other!) makes sense, because GND2 is sensed by an instrumentation amplifier (IA) and GND3 is the remote ground of a current source (IIA).

    But notice the two ground points labelled "GND1" in your picture: They have to be identical. :-)

    The XTR305 is a remarkable chip...

    Kai
  • 0 in reply to kai klaas69
    TI__Genius 11135 points
    Lucas

    We haven't heard back from you so we assume this answered your question. If you need additional help just post another reply below.

    Thanks
    Dennis