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TAS5534/38 SDOUT Mode

Sadanori Kato
Guru 36490 points
Other Parts Discussed in Thread: TAS5538, TAS5624A, TAS5558

Hi,

Could you please give us your advice for the sdout mode ?
We understand that the I2S out port can be used for wireless subwoofer function, I2S serial data is output from the sdout port since TAS5534/38 has the dolby down mix feature if setting 1b to D0 of the 0x04 register.
Does TAS5534/38 actually have this feature ?
Moreover, does those devices keep output sample rate at 48KHz irrespective of input sample rate by the SRC function if having ?

Best regards,
Kato

  • 0
    Guru 36490 points

    Hi,

    We have additional information.
    The output data is appeared from the sdout port depending on the input sampling rate as below when inputting 32kHz, 44.1kHz and 48kHz as the sampling rate.
    Is this working correct for TAS5534/38 although it seems that the mention content of the data sheet is wrong ?
    So, can TAS5534/38 fix the sdout data to 48kHz by changing the register settings ?

    Input Sampling Rate ---> Output Sampling Rate for SDOUT
    32kHz               ---> 32kHz
    44.1kHz             ---> 44.1kHz
    48kHz               ---> 48kHz

    In addition, it seems that the mention content of the data sheet is wrong as below since TAS5534/38 does not work as it is mentioned in the data sheet when verifying the dolby down mix feature.
    We understand that the input data of dolby down mix is directly input the I2S input of SDIN1, SDIN2 and SDIN4 as the following schematic.
    Is our understanding correct ?

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Mastermind 27850 points
    Hi Kato-san,

    These inputs will go through the cross bar mixers, but to be a Dolby down mix, the cross bar mixers will need to be pass through. So the diagram should be corrected to show the input crossbar mixers. These might have been left out as they need to be pass through if you want a Dolby down mix output.

    You are correct that the output sample rate of SDOUT will change with the input sampling rate as there is no ASRCs in the TAS5534/38.

    Justin
  • 0 in reply to Justin Bohr
    Guru 36490 points

    Hi Justin-san,

    Thank you for your response.
    I understood.

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Justin-san,

    We have an additional information.
    The relation of the input sampling rate and the output sampling rate is shown as below when verify the evm of TAS5538 and TAS5624A again.
    The results that we have reported previously was a characteristic of TAS5534.
    Is this result proper?

    Input Sampling Rate ---> Output Sampling Rate for SDOUT
    32kHz               ---> Not output the signal(GND Level)
    44.1kHz             ---> 44.1kHz
    48kHz               ---> 48kHz
    96kHz               ---> 96kHz
    192kHz              ---> Not output the signal(GND Level)

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    Guru 36490 points

    Hi Justin-san,

    I have evaluated TAS5538 & TAS5624A again since there was an error in an evaluation method.
    In addition, I have evaluated TAS5558 & TAS5624A.
    It seems that TAS5558 works normally as it is mentioned in the data sheet.
    This issue have been closed since I have already informed our customer of your information and our evaluation results.

    <TAS5538 & TAS5624A Evaluation Result>
    Input Sampling Rate ---> Output Sampling Rate for SDOUT
    32kHz               ---> 32kHz
    44.1kHz             ---> 44.1kHz
    48kHz               ---> 48kHz
    96kHz               ---> 96kHz
    176.4kHz            ---> SDOUT is not output(LRCLKO=88.2kHz)
    192kHz              ---> SDOUT is not output(LRCLKO=96kHz)

    <TAS5558 & TAS5624A Evaluation Result>
    Input Sampling Rate ---> Output Sampling Rate for SDOUT
    32kHz               ---> 48kHz
    44.1kHz             ---> 44.1kHz
    48kHz               ---> 48kHz
    96kHz               ---> 48kHz
    176.4kHz            ---> 44.1kHz
    192kHz              ---> 48kHz

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Mastermind 27850 points
    Hi Kato-san,

    Thank you for sharing this information.

    Justin