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TPA6203A1: TPA6203A1 pop noise

sundy xie
Intellectual 525 points
Part Number:

Dear,

We use TPA6203A1 in the product. Figure 1 is the exact schematic.

Figure 1

When we insert earphone, it's single end output. And there is pop noise in the earphone(C2007 is the Cbypass).(Figure2 is the Vo+ wave )

If we remove the C2007(Cbypass) the pop noise is lower.(Figure3 is the Vo+ wave )

Could you give some advice how to eliminate the pops when we use single end output? 

Thanks!

 

  • 0
    Intellectual 525 points

    sundy xie said:

    Part Number: TPA6203A1

    Dear,

    We use TPA6203A1 in the product. Figure 1 is the exact schematic.

    Figure 1

    When we insert earphone, it's single end output. And there is pop noise in the earphone(C2007 is the Cbypass).(Figure2 is the Vo+ wave )

    If we remove the C2007(Cbypass) the pop noise is lower.(Figure3 is the Vo+ wave )

    Could you give some advice how to eliminate the pops when we use single end output? 

    Thanks!

     

    Figure2

    Figure3

  • 0 in reply to sundy xie
    TI__Mastermind 20085 points
    Hi Sundy,

    This device can be used without a bypass capacitor if this resolves the pop noise problem, so you can use like this. Keep in mind that removing the bypass capacitor slightly worsens power supply rejection ratio(Ksvr), but a slight decrease of Ksvr may be acceptable.

    Best Regards
    José Luis Figueroa
    Audio Application Engineer
  • 0 in reply to José Luis
    Intellectual 525 points
    Hi Jose,

    As we learned, there is a Vdd/2 voltage in the polarized capacitor(C2002/C2004) after we shutdown the PA. If we EN the PA, the Vdd/2 in the polarized capacitor will discharge firstly.The discharge voltage will produce POP noise.
    Removing the bypass capacitor can't resolve this pop noise issue absolutely.And we can't accept the PSRR is worse yet.
    Now we want you help to check :
    1.the Vo+/Vo- status of TPA6203A1 when the SHUTDOWN is pull down.
    2. the TPA6204A1/TPA62011A1 Vo+/Vo- status when the SHUTDOWN is pull down.. Whether it's same with TPA6203A1?

    Could you give some advice about this single end output application to eradicate the pop nosie when we EN the PA? Thanks!
  • 0 in reply to sundy xie
    TI__Mastermind 20085 points
    Hi Sundy,

    1. That's right.
    2. These kinds of devices have the same behavior, so their outputs are pulling down in shutdown mode.

    It is not very clear when the device gets pop noise, so Could you explain when the device gets pop noise in detail?

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer
  • 0 in reply to José Luis
    Intellectual 525 points

    Dear,

    We repalced TPA6203 with TPA6204. Remove the external feedback resistor  and change the RI value accordingly. (single output with polarized capacitor in the output Vo+)

    There is the test result.

    1. When we pull up the SHUTDOWN of TPA6204, the VDD/2 Voltage in the polarized capacitor is discharged to 50mV. However, the VDD/2 can't be discharged in TPA6203.

    There is the Vo+ wave when we pull down/up the SHUTDOWN of TPA6203/TPA6204.

    Could you give some explanation about the difference output in Vo+ of TPA6203 and TPA6204?

    Thanks! 

    Sundy

  • 0 in reply to sundy xie
    TI__Mastermind 20085 points

    Hi Sundy,

    The biggest difference seems to be that TPA6204A1 has an internal feedback network.
    You can refer Single-Ended Input Pop Reduction for TPA6203A1 application report to find one way to reduce pop noise. Keep in mind this method is implemented with a differential configuration, perhaps this could work in your application.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer

  • 0 in reply to José Luis
    Intellectual 525 points
    Hi Jose,

    We have tried the method that adding a resistor in the Vo+, and the pop noise is lower. But we don't want to change our design.
    TPA6204 can meet our requirement. Now we only want to learn the reseason of POP noise with single output in TPA6203.

    Sundy
  • 0 in reply to sundy xie
    TI__Mastermind 20085 points
    Hi Sundy,

    It seems that TPA6204A1 has an internal circuit for a fast start-up with minimal pop.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer