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TLV320DAC32: Pop noise when unmute

Brian Zhao
Prodigy 540 points
Part Number: TLV320DAC32


Hi,

My customer is using TLV320DAC32 and they found pop noise when unmuting the device.

Below are the codes they used to unmute TLV320DAC32. Could you please help check if any software workaround to fix this?

 codec_write(0x2B,0);               //Left DAC

         codec_write(0x2C,0);               //Right DAC

         codec_write(0x2F,0x80|0);    //DAC_L to HPLOUT

         codec_write(0x40,0x80|0);    //DAC_R to HPROUT

        

         codec_write(0x33,0x0D);         //HPLOUT

         codec_write(0x3A,0x0D);        //HPLCOM

        

         codec_write(0x41,0x0D);         //HPROUT control volume

         codec_write(0x48,0x0D);       //HPRCOM

Many thanks.

Best Regards,

Brian Zhao

  • 0
    TI__Guru** 112975 points
    Hi Brian,

    I'll work on this today and will share my findings with you today's end of the day at the latest.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Guru** 112975 points
    Brian,

    Regarding the default value of register 40 from page 0, it is default 0x00. Although you could write the desired value into this register just to ensure that the value is actually present in that register. There are some registers, like HPxCOM that need to be written even to the default values to operate correctly.
    About the pop mitigation, this device does not have de-pop circuitry, like TLV320DAC3203. I'm trying to find the best combination of startup commands for best pop performance possible when using the device in stereo differential mode.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Prodigy 540 points

    Hi Ivan,

    Many thanks for your quick response.

    Looking forward to your reply about the pop mitigation.

    Best Regards,

    Brian Zhao

  • 0 in reply to Brian Zhao
    TI__Guru** 112975 points
    Hi Brian,

    Unfortunately I have not found any perceivable difference by changing the order of the startup commands. And also, as mentioned before, this device does not have de-pop circuitry.
    Are there DC blocking caps at the outputs of the device? I understand that the loads are connected in BTL mode between HPxOUT and HPxCOM, but perhaps adding the DC blocking caps could help with the pop.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Prodigy 540 points

    Hi Ivan,

    How about register 40? Whether that can help?

    thanks.

    Brian Zhao

  • 0 in reply to Brian Zhao
    TI__Guru** 112975 points
    Hi Brian,

    Register 40 is soft-stepping for volume control, it would avoid pop when changing volume level. But unfortunately this is different than power-up

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    TI__Prodigy 540 points

    Hi Ivan,

    We also tried to reduce the volume level to a very low level when in-muting the device. Then we change the volume level up step by step (register 64 and register 47). But it still have the pop noise. Do you have any idea to improve that? Whether register 40 can help here?

    Thanks.

    Brian Zhao

  • 0 in reply to Brian Zhao
    TI__Guru** 112975 points
    Hi Brian,

    It would depend on when the pop occurs. Register 40 can help if pop occurs when adjusting the volume level. If the pop occurs when enabling the output driver, then register 40 could not help as it only affects during volume change.
    Other devices, like TLV320DAC3203 have some circuitry to mitigate the pop, and what this circuitry does is to create a ramp-up for the output drive power-up.

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