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TPA2011D1: Pop noise

Shu-Cheng LIN
Guru 11785 points
Part Number: TPA2011D1


Hi Sirs,

Sorry to bother you.

Our schematic as below.

Audio-NEW.pdf

When the Win10 logo appears before entering the OS, we found speaker had bo noise and looks is caused by AMP to be enable. How can I improve this problem?

 
Thank you

  • 0
    TI__Guru* 84915 points

    Hi, Shu-Cheng,

    Our team will take a look at this issue. We will answer as soon as possible.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0
    TI__Guru** 110745 points

    Hi Lin,

    I would recommend to use the same component values for both IN+ and IN-, the schematic shows different resistor and capacitor values on each of them.

    Using single-ended input makes the device more susceptible to pop noise. This noise is caused by mismatch in the input capacitors charge/discharge. If you use different values on each part of the input, you may be even increasing this mismatch.

    Some recommendations to reduce pop noise are:

    • Use Differential inputs if possible
    • Use precision components like 1% resistors and X7R capacitors
    • Reduce input coupling capacitors
    • If using Single-ended inputs, you can test different capacitor values for the unused input, perhaps there is a better impedance match with the used input

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    Actually Single-ended inputs this section cannot be modified.

    The capacitor resistors already use X7R and 1% precision resistors.

    So is there any more advice or design guide?

    Now my approach is use realtek to modify the FW into the OS.

    Let EAPD pull high to open AMP, but there are other side effects.

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Guru** 110745 points

    Lin,

    Those are the recommendations that are usually followed to reduce the pop noise.

    Most important is to match the components between IN+ and IN-

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    Our test results as below
     
    The capacitors on the IN+ IN- are replaced by 100nF & 150Kohm or both are replaced by 220nF & 75K.

    The Bo noise is caused by the AMP enable. It is not very effective to match by the input.

    Please help provide more idea for us if possible. Thank you.
  • 0 in reply to Shu-Cheng LIN
    Guru 11785 points

    Hi Sirs,

    Sorry for pushed, have any update on here?

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Guru** 110745 points

    Lin,

    Is there a chance you can take some scope captures of the inputs during the pop transient?

    Perhaps you can check the difference between the input pair and adjust input capacitors independently to reduce the difference during the transient.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Guru** 110745 points

    Hi Lin,

    Do you have further questions or comments about the last post?

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators