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TAS5538/TAS5624A Pop Noise Issue when HP_SEL is Asserted to Low

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

Hi,

The pop noise occurs when HP_SEL is asserted to low on the customor board.
However, the pop noise does not occur when PDN and HP_SEL are simultaneously asserted to low.
So, we will ask you as below.

Q1.
Does TAS5538 have the special function such as the output phase adjustment when PDN and HP_SEL are simultaneously asserted to low?

Q2.
Does TAS5538 cause any problem when PDN and HP_SEL are simultaneously asserted to low?

Best Regards,
Kato

  • 0
    TI__Mastermind 33420 points

    Hi Kato-san,

    Thanks for drawing the timing diagram.  That makes it easy to understand.  I really appreciate that.

    Answer 1:  No, it has no special function with output phase adjustment when PDN and HP_SEL are asserted.  Actually at the system level, phase adjustment is only done while the device is in mute or powered down.  This is to prevent pop noise.  We have not tested the phase adjustment (by this I assume the customer is changing inter-channel delay register) on the fly, i.e. during operation, PWM is running.

    Answer 2:  There should not be any issue with asserting PDN and HP_SEL low simultaneously, since they are just logic/discrete signals.  During power down state, the device will not have clocks running ... but at the start of powering down, there is ramping (control) down period so the device should catch HP_SEL.   We have not tested this scenario, so please ask the customer to verify this in their system to be sure.

    Best regards,

    Tuan

  • 0 in reply to Tuan
    Guru 36490 points

    Hi Tuan-san,

    Thank you for your quick response.
    I understood and will contact you if I have any questions.
    I greatly appreciate your cooperation.

    Best Regards,
    Kato