LM49450: Asking for the LM49450 power sequence recommendation

Genius 16505 points

Part Number: LM49450

Hi Team,
Customer uses LM49450. They found the pop noise on the headphone while AC ON/OFF.
Do you have the recommended power sequence for the LM49450?

Thanks,
SHH

3 Replies

  • Hi SHH,

    There is not a power sequence specified in this device data sheet. What is the sequence you're following?
    CH2 is headphone power supply voltage? Have you tried to perform a different powering up sequence? Perhaps enabling headphone supply voltage later in time.
    When powering down the device, is the headphone driver muted?

    Best regards,
    -Ivan Salazar
    Audio Applications Engineer - Low Power Audio & Actuators
  • Genius 16505 points

    In reply to Ivan Salazar:

    Hi Ivan,
    This project was transfer to me. So customer told me that they do not do any power sequence control for the pop noise.
    So can you provide the suggested power sequence for them?


    Thanks,
    SHH
  • In reply to SHH:

    SHH,

    As there is not a specified power sequence on device literature and I don't have an available board for testing I can only give suggestions.
    You could try to power up +2.5V later in time, perhaps power this up at the end of power up sequence.
    Regarding power down, you could try to first mute the device using reg 0x00 bit 2 = 1 and then continue with power down sequence.

    Best regards,
    -Ivan Salazar
    Audio Applications Engineer - Low Power Audio & Actuators