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Original question:

PGA4311EVM: PGA4311EVM

PGA4311: PGA4311 - Zero Crossing

Stephen Gilbert52
Prodigy 140 points
Part Number: PGA4311

The PGA4311 has a pin (ZCEN) which will enable the gain (volume) to be changed only on an audio zero crossing when this pin is pulled high. Would there be an operational problem with pulling this ZCEN pin high via a resistor all of the time instead of having the main controller pull it high only on a volume change?  I can't think of a reason why you would want to change the volume on anything other than a zero crossing in order minimize audio noise on a gain change.

Thank you  for your response.

Stephen Gilbert

Staff Engineer

NORTHROP GRUMMAN

Mission Systems

5000 Bradford Blvd Suite 100

Huntsville, AL 35805

Phone: (256) 327-6772

stephen.gilbert@ngc.com

  • 0
    TI__Guru 55466 points
    Hi Gilbert,

    Yes, a pull up resistor can be placed on the ZCEN pin to the digital power supply (VD+) in order to have the zero crossing detection function always active.

    You are correct, most audio applications will use the zero crossing detection function enabled to provide noise-free level transitions. However, the PGA4311 could be used in non-audio applications or used in systems where the user requires tight control on when the gain change occurs. For flexibility, the user has access to enable or disable the zero crossing detection function.

    Thank you,

    Kind Regards,

    Luis