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AFE5818: AFE5818 Ground Concept

Stefan2005
Prodigy 50 points
Part Number: AFE5818

Hi,

Now we are designing a daughter card with AFE5818, DAC and other Digital ICs. One Connector is used for power supply and digital signal transfer. the other connector is used to connect to analog sensors. We are planing to use separate analog and digital voltage (split power planes). But The Ground concept is not clear, if one Ground Plane shall be used or There shall be the analog and digital planes in the circuit separability and connected together just at the primary side( at the connector).  

Regards

  • 0
    Prodigy 50 points
    If possible, every power rail shall have own ground plane to avoid the common ground. In a mixed signal design, typically the ground will be splitt in to analog and digital ground. In this case the signal traces shall be not routed cross over two grounds.
  • 0
    Prodigy 50 points
    any suggestion for this ground topic?
  • 0 in reply to Stefan2005
    TI__Mastermind 49956 points
    Hi Stefan,

    As outlined in the AFE5818 datasheet, either single ground plane or partitioned ground plane is ok. If you are going with partitioned ground planes, additional care must be taken such that there is minimal interactions between analog and digital circuitry just like you have mentioned.
    For this configuration, you could tie the AVSS and DVSS grounds together at the power connector in a star layout.
    You can also refer to the grounding scheme in the AFE5818EVM (refer AFE5818EVM user guide for reference).