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TLV320AIC3204: Crosstalk Issue

Sadanori Kato
Guru 36540 points
Part Number: TLV320AIC3204


Hi,

The crosstalk to the headphone output via the IN1R input occurred, but the IN1R input isn't routed to the headphone output on P1_R13.
In addition, the crosstalk doesn't occur if inputting the audio signal to IN2R input.
So, could you please tell me that reason why the crosstalk to the headphone output occurs if inputting the IN1R input ?

Best regards,
Kato

  • 0
    TI__Guru 57800 points

    Hi, Kato-san,

    The input IN1R can be directly connected to the headphone outputs for bypass operation mode, however, there should be no effect of the input signal over hp output if the path is not configured with register P1_R13. IN2R does not have a bypass option to the HPR output.

    The crosstalk you are mentioning should not occur, but I wonder if you are doing a proper hardware and software reset to the device before powering-up. Otherwise, it is possible that the register is not properly reset to the default value (IN1R is not routed to HPR). Can you please verify that the device is kept in reset state until all the supplies are provided and that a SW reset is implemented as soon as the register configuration starts?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36540 points

    Hi Diego-san,

    Thank you for your quick response.

    Today, I visited and discussed with our customer, but the root cause isn't find out.
    The crosstalk to the headphone output occurs even if inputting the audio signal(1.6Vpp ~ 2.2Vpp) to IN1R after the power-up, so I am confirming whether the IN1R is damaged.
    Could you please give me your advice about this sympthom ?

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru 57800 points

    Hi, Kato-san,

    This is not a normal behavior for this device, but it is unlikely that damage on IN1R could cause this problem. If there is damage, it would be on the output headphone mixer.

    Do you know if it is possible to replicate this issue over different boards?. Have customer tried to use the EVM to check if this behavior can be replicated?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36540 points

    Hi Diego-san,

    Thank you for your support.

    Yes, this issue is replicated on the two test boards, but the EVM hasn't been verified.
    So, could you please try to check whether this issue is replicated by using the EVM as I don't have it ?

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru 57800 points

    Hi, Kato-san,

    Sorry for the delay. I ran a quick test in the EVM and under normal operation mode, the crosstalk between IN1x and the headphone outputs is not happening. I was able to get a similar behavior only when applying a large signal to the  IN1x inputs, with an amplitude above the recommended input voltage spec, which is not compliant with the correct operation of the device. Please verify that the input signal in IN1x is not above the recommended input voltage values.

    It is possible that the crosstalk is caused under this situation by a saturation on the INx signal path.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36540 points

    Hi Diego-san,

    Thank you always for your support.

    I just got an additional question from our customer.
    Is my understanding correct that the crosstalk occured only when applying a large signal to the IN1_L and IN1_R in your verification ?
    In other words I understood that the same symptom didn't occur when applying a large signal to the IN2_L, IN2_R, IN3_L and IN3_R.
    Could you please give me your comment ?

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru 57800 points

    Hi, Kato-san,

    Correct, crosstalk occurred only when a large signal is applied to IN1L and IN1R. This does not occur if the same input signal is provided to IN2 and IN3 (please consider that applying a signal with such a high amplitude is not recommended). This behavior may be related to the direct interface of IN1x and HP drivers through the bypass path.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Guru 36540 points

    Hi Diego-san,

    Thank you for the explanation.

    I understood and will inform this information to our customer.

    Best regards,
    Kato