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TLV320AIC3111: Pop Noise Issue

Sadanori Kato
Guru 36540 points

Part Number: TLV320AIC3111

Hi,

The pop noise occurs when routing DAC output signal to Class-D amplifier and headphone amplifier with GUI as below.
In addition, the pop noise doesn't occur if placing the analog attenutation block in mute but the pop noise occurs when changing the analog attenuation setting.
So, could you please tell me how to minimize the pop noise which you would recommend when changing the DAC output signal routing ?

Best regards,
Kato

  • 0
    TI__Mastermind 30230 points
    Hello Kato-san,

    There are a couple options to reduce or eliminate this.

    1. Mute the analog attenuation block before you switch, then unmute.
    2. If you absolutely must switch this while the analog attenuator is not muted, then you should mute the source (Aux 1, Mic1, or DAC) before it is connected, and then unmute after.

    Remember for both cases, when Soft-stepping is enabled, it will take some time for the mute to fully enable. This is because the soft-stepping feature ramps the output down at a rate of one step per sample (by default, one step per 2 samples is also an option). So if the DAC volume control is set at 0dB, the minimum is -78dB, and the steps are 0.5 dB steps. Then the delay should be 156/Fs secs.
    So if you don't put a short delay between the mute command and the path switch command, your soft step function could be in the process of running, and still allow a pop noise.

    best regards,
    -Steve wilson
  • 0 in reply to Steve-Wilson
    Guru 36540 points

    Hi Steve-san,

    Thank you for your prompt reply.

    I understood.

    Best regards,
    Kato