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Asking for the TA5717 line out amp pop noise

SHH
Mastermind 32206 points
Other Parts Discussed in Thread: TAS5717

Hi Team,
My customer used the TAS5717 on the monitor application.

They used the analog amp as line out amp.
They found the pop noise while connecting to the external protable speaker.

The line out amp input signal is from scalar directly.
Experiment we did.
1. To isolate the issues, my customer shorted the input to GND. The pop noise is still existing.
2. pull down the HP_SD pin, it still have the pop noise whlie the AC power turned on. is that make sense? RD think use the HP_SD pin should not have the pop noise.


Did you have the sequence for the timing sequence to avoide the line out pop noise( register 0x05, HP_SD pin33, PDN pin 19 )?

e2e.ti.com/.../1103769
from the E2E post, I did not see the conclusion for the sequence.

Due to customer information is not proper post here, please let me know if you need the schematic.


Thanks,
Scott

  • 0
    TI__Guru 57800 points

    Hi, Scott,

    There should be no pop issues if /HP_SD is held low until the HPVDD is stable. After the power supply is stable, the AC coupling capacitors should be charged, avoiding any possible pop. You may try muting the volume of the Line out driver before asserting /HP_SD to high. So, a basic sequence would be:

    • Keep /HP_SD in low state.
    • Turn ON HPVDD.
    • Mute the volume of the Driver:Set /HP_SD to High.
      • If  Bit D3 of  Register 0x05 is 1, the driver volume is controlled by registers 0x08/0x09 (default 0dB).
      • If Bit D3 of  Register 0x05 is 0, the driver volume is controlled by register 0x0C (default 0dB).

     No other change is required for register 0x05 as the driver is used with analog input and the /HP_SD pin is controlled externally. 

    Please send me the schematic so I can check if there is any other possible issue. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer