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TPA3123D2: Analog Ground & Power Ground

Vitor Silva1
Prodigy 120 points

Hi,

 

I am configuring a TPA3123D2 and I am interested to know more about the power ground and analog ground! Why this separation?? Because after all these two grounds are connected in Power Ground and so they are the same ground!

 

Thank you

  • 0
    TI__Mastermind 37045 points

    Hi Vitor,

    They are the same ground with different names. Same name would have avoided this confusion. Connect all the ground pins with a solid ground plane. I would suggest follow the EVM layout for your design.  

    reg,

    Paul Chen

    Audio Apps

  • 0 in reply to user5276421
    Prodigy 120 points

    Hi Paul,

    Thank you for your feedback!

    I am some confused about this two different grounds! I made some research about this issue and I found some information that explain the diferences about this two grounds. The main reason is about the noise introduzed by different voltages (signal and power), and the solution will be connect the two grounds (in this case in termal pad) via inductor.

    Can you give me some feedback about this technique and it can be applicable to this structure? If yes, can you recommend a value for this inductor?

     

    Thank you a lot,

    Vitor

  • 0 in reply to Vitor Silva1
    Prodigy 230 points

    No, you must connect the two ground directly.

    Regarding noise, I presume that they refer to ground loop. In that case, you just need to avoid routing heavy current flow (output stage to power ground) near any sensitive analog circuitry (input stage, feedback and compensation to analog ground). Merely separating the two ground (ex. output stage to the right of IC and input stage to the left of IC) and only connect them at one point (usually at the thermal pad) is sufficient.

    If noise is critical, then consider to use amp with differential input.

  • 0 in reply to ArdWar
    Prodigy 120 points

    Hi,

     

     Thank you a lot! But I should connect the 2 grounds directly only in termal PAD? Or short all ground inputs (signal & power) at the input connectors?

    Thank you