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TAS5711: Asking for the TAS5711 EVM pop question

Part Number: TAS5711
Other Parts Discussed in Thread: TAS5805

Hi Sir,

 My customer would like design TAS5711. however, there is pop noise on the system

so customer uses EVM to duplicate the pop noise.

While using TAS5711 EVM board, the pop noise also heard,

and even if I tune down the volume, this pop noise still exist when “shutdown” status from “check” to “uncheck”

 

 

BR,

SHH

  • Hi SHH,

    Can you provide more system level details? Did they do any modifications to the EVM? If they did what were the changes? What is the speaker they are using? What's the speaker impedance? What's the PVDD level they used? 

  • Hi Robert,

    EVM board is no chang.

    The speaker is 4 ohm

    The PVDD is 20V and Vin is 5V

    And from Oscilloscope measured at SPK connection, an impulse appeared when the system is leaving from “shutdown” mode.

    BR,

    SHH

  • Hi,

    So the pop happens the moment when the PWM starts switching, right? 

    Could you please set the SOFT MUTE register 0x06 to soft mute all the channels and see if it improves a little? 

    BTW, the TAS5711 is a quite old device... We have latest TAS5805 and TAS5825 to replace it with better performance. Would you consider these devices?

    Thanks!

    Regards,

    Sam

  • Hi Sam,

    0x1A register is for the soft start/stop application. After changing 0x1a to 18, noise is more quiet, but it is not acceptable if user in quiet place.

     By the way, once 0x1a is disable (80), this pop noise is disappeared.

    and does it have any other concern if 0x1a = 80?

    BR,

    SHH

  • Hi,

    If the soft start is disabled, the output common mode voltage will ramp up very fast. I think this moves the differential voltage(aka the "pop") during the startup to higher frequency range, making it inaudible.

    I didn't see much drawback to disable it.

    Regards,

    Sam