ground noise in pcb

Discussion in 'The Projects Forum' started by satishreddy, Jul 19, 2012.

  1. satishreddy

    Thread Starter New Member

    Jul 19, 2012
    6
    0
    Hello,

    we have designed a board using aduc7026 microcontroller but we are facing noise problem as we have different grounds for Vref(gnd) , vcc(gnd),avdd(gnd),24gn connected separately to connector.I think noise problem is because grounds so please help me to come out of this problem.

    Waiting for the reply
    Regards
    satish
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    It would be very nice of you if you could post the schematic of the board and everything that is connected to it including power supplies, along with the drawing of the board.
    If you don´t, no one can help you.
     
  3. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    Do not connect analog grounds (noisy) to digital grounds. The noise from the analog will be coupled right to the digital side.
     
  4. satishreddy

    Thread Starter New Member

    Jul 19, 2012
    6
    0
    ya analog and digital gnd are separate as i mentioned all the grounds are separate but still noise is generated.i think the problem is because i have not connected all gnd in a star.since modifying gnds is difficult because pcb is manufactured.Please me help me.

    Thanks & Regards
    satish
     
  5. osx-addict

    Member

    Feb 9, 2012
    122
    9
    I think a schematic is in order.. per the above request by Kubeek..
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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  7. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    You have to connect the two grounds together at some point (single point ground) if there is any exchange of signals between the analog and digital circuits (which there usually is). The trick is to do the connection at the right spot.

    And you have it backward. It's the digital ground that is typically more noisy than the analog. ;)
     
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