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TAS5751M: Question of TAS5751 with 3-wire I2S Input

Part Number: TAS5751M
Other Parts Discussed in Thread: TAS5717

Hi Sirs,

According to the datasheet, the TAS5751 supports 3-wire I2S with no MCLK. Would you please provide tips how to handle un-used MCLK signal and how to program the TAS5751 to support 3-wire I2S? Should we connect the MCLK and BCLK together as we did with the TAS5717/19?





Thank you and Best regards,

Wayne Chen
07/17/2019

  • Hi Wayne,

    TAS5751 3 wires clock configuration:

    'The description that “3-wire I²S mode(no MCLK required)” in datasheet means that MCLK can be connected to SCLK because they can accept the same frequency clock for some cases. So in order to make this, MCLK and SCLK should be tied externally. It means that I2S only works when SCLK is in the range of 2.8224~24.576MHz. 

    If MCLK is not provided, the amplifier’s internal oscillator will generate the internal clock required for the amplifier’s operation. In this operation mode, the amplifier will not stream audio content through the outputs until a valid MCLK is provided.

    Usually, 48kHz Fs and 32bits mode are used, then SCLK is 3.072MHz, which can be also used for MCLK. '

    Regards,

    Matthew

  • Hello Matthew,

    Thanks a lot. With MCLK and BCLK connected together, can the TAS5751 support the following sample rates?  8kHz, 11.025kHz, 16kHz, 22.025kHz, 32kHz, 44.1kHz, 48kHz.

    According to the TAS5751 datasheet, we should write 0x1B = 0x00 (trim) firstly (refer to my enclosed example), hoever, the CFG generated from PPC3 GUI writes 0x06 and 0x05 command firstly. Would you please confirm which one is correct?

    Thank you and Best regards,

    Wayne Chen
    07/17/2019 

    TAS5751_PPC3_Default.cfg

    56test.cfg  

  • Hi Wayne,

    The same as TAS57xx open loop devices. Only 44.1k and 48kHz FS can be supported with 3 wires I2S.

    Regarding 0x1B osc trim, PPC3 GUI only dumps out step 4 - Digital Audio Processor Configuration. So you should manually add 0x1B write 0x00 at 3rd step of datasheet 8.2.1.2.5.1 Start-Up Sequence.

    Regards,

    Matthew

  • Thanks for the info.