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LM4666: LM4666

Part Number: LM4666

Hi

I am trying to use an LM4666SD to drive two speakers they are CUI Inc. CMS-15113-078S-67 it is being driven by a SGTL5000XNAA3/R2 but I get no output am I missing something?

LM4666SD.docx

  • Hi, Gregg,

    The schematic seems to be correct. And the speaker loads also seem to respect all the LM4666 conditions.

    I have few recommendations, could you try them and let me know your observations, please?

    1.- I see in your schematic that the device is configured in single-ended mode (only VIN_R- and VIN_L- are used). Could you check with a scope if you have an audio signal at the VIN_R- input? If so, could you provide its voltage level and frequency?

    2.- Could you verify the VIN_R- and VIN_L- output level when you power up and enable the device? Could you try then without a speaker connected?

    3.- Could you verify the VDD level with a scope or multimeter? Is the voltage stable?

    Please let me know if you have observations on this. This could give us a better idea of what could be the root cause.

    Thank you.

    Best regards,
    Luis Fernando Rodríguez S.
  • VDD is 3.3V
    Gain select is 3.3V
    Shutdown is 3.0V
    i am in the process of checking signal levels
    I am playing a song through Android so not sure the frequencies
  • Hi, Gregg,

    Thank you for your feedback.

    Any information about the inputs and outputs audio signal level or scope captures you could provide will be useful. I didn't find anything wrong in your schematic. So, this information could help us to isolate the root cause.

    Best regards,
    Luis Fernando Rodríguez S.
  • Hi, Gregg,

    Excuse me, do you have any feedback on this? Were you able to take the captures of the inputs and outputs as I recommended in my first response?

    Thank you.

    Best regards,
    Luis Fernando Rodríguez S.
  • So changed the capacitors to .39UF no Help at high volumes my codec would stop functioning. As it turns out the problem was L2 my AGMDM was noisy from the amp I removed the inductor and used a 0 ohm and my problems went away.