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PCM1803A: Connection processing of logic pins for PCM1803A

yoshiki hasebe
Mastermind 6385 points
Part Number: PCM1803A


Dear Sirs,

My customer asked us about connection processing of logic pins for PCM1803A.

Is a pull-up resistor and pull-down resistor necessary at LOW / HIGH on the Logic pin shown below?
PIN 8, 16, 17, 18, 19, 20
After checking the datasheet, these input pins were Schmitt trigger inputs.
Also it was pulled down internally by 50 kΩ.
For this reason, I think that it is necessary to fix both the pull-up resistor and the switch as necessary, and to fix the pull-down resistor and to use the switch.
Is this correct?

Best Regards,

Y.Hasebe

  • 0
    TI__Guru 57800 points

    HI, Hasebe-san,

    Could you please provide more information about customer's use case with the mentioned switch?. This device can be operated without the pull-up and pull-down resistors. If a switch is used, probably the best would be to add an RC network to damp the intermittent state of the signal caused by the mechanical movement of the switch.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Mastermind 6385 points

    Hello Diego-san,

    Thank you for your reply.

    I'm sorry not enough explanation.

    My customer does not use switch.

    They are concerned about simply switching L / H, not using SW devices.

    In that case, I think that it is good without pulling up or pulling down.
    Is this correct?

    Best Regards,

    Y.Hasebe

  • 0 in reply to yoshiki hasebe
    TI__Guru 57800 points

    Hi, Hasebe-san,

    Thanks for the feedback and clarification. Correct, the change between the state of the pins can be changed without the external resistors as this device has an internal pull-down resistor.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Mastermind 6385 points

    Hello Diego-san,

    Thank you for your reply.

    I understand your comments.

    I will explain to my customer.

    Best Regards,

    Y.Hasebe