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TAS5756M: Question about GVDD_REG power supply

Guru 15020 points

Replies: 20

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Part Number: TAS5756M

GVDD_REG power supply specification is not described in datasheet.

Waveform for startup sequence is attached below;

・On startup to 10 sec: 5.4V output and the after is 6.8V output.

・After I2C communication(Reset), GVDD is dropped to 5.4V for 1 sec and after become 6.8V.

Please let me know about two points question below;

①Is above waveform correct operation?

②Please let me know timing for read Vspk_GAIN/FREQ's  DC voltage.

Best regards,

Satoshi

  • Hi Satoshi-san,
    We are looking into this and will get back you soon later.
    Best regards,
    Shawn Zheng
  • Guru 15020 points

    In reply to Shawn Zheng:

    Shawn Zheng-san

    Thank you for reply,
    I understood your status, I looking forward any update later.

    Best regards,
    Satoshi
  • Hi Satoshi,

    What are the i2c commands you sent in your measurement?


    Andy
  • Guru 15020 points

    In reply to Andy Liu SH:

    Andy-san

    I attached I2C command data, please see below.

    I2C_command.xlsx

    Best regards,

    Satoshi

  • Guru 15020 points

    In reply to Satoshi:

    If there lack information, please let me know.
    I will confirm to customer.
  • In reply to Satoshi:

    Hi Satoshi,

    Let me explain why you would see the transition from 5.4V to 6.8V (See what is highlighted below). 

    After the TAS5756M is powered on, the GVDD_REG voltage will be around 5.4V if NO I2S clocks are provided. In addition, its voltage will be close to 7V when the TAS5756M is fed with I2S clocks and data.

    The transition from 5.4V to 6.8V in your scope capture is because the I2S clocks in the customer systems are starting to run at that time. 

  • In reply to Satoshi:

    The second transition from 6.8V to 5.4V is due to the following i2c command. Basically, the GVDD_REG voltage drops down to around 5.4V when it goes to the standby mode.

    Andy

  • Guru 15020 points

    In reply to Andy Liu SH:

    Andy-san

    Thank you for advice, I understood very much.
    I looking forward answer about ②.

    Best regards,
    Satoshi
  • In reply to Satoshi:

    As far as I know, the gain and switching frequency settings are latched during power-up and cannot be changed while the device is powered.

    Andy
  • Guru 15020 points

    In reply to Andy Liu SH:

    Andy-san

    Sorry for additional question about ②,

    When power-up timing, which is correct for 5.4V or 6.8V?
    If 5.4V is correct, TAS5756M can't set 26dB / 8 x fSYNC by datasheet Table 15.
    Is there any measure?

    Best regards,
    Satoshi

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