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PCM1863 - unuse pins

Other Parts Discussed in Thread: PCM1863, PCM1861

Hi all,

Would you mind if we ask PCM1863?

Our customer will not some pins, so could you let know us how to set following unused pins?

<Unused pin>
・MIC BIAS(pin-5): Open? Or, AC coupling(capacitanse) with connecting to GND?
・Unused analog input pins(VINLX, VINRX):AC coupling(capacitanse) with connecting to GND?
・XO(9pin), XII(10pin) (in case of no use cystal): Open?

Kind regards,

Hirotaka Matsumoto

  • Dear sir,

    If you have some information, could you let know us above guestions?

    Kind regards,

    Hirotaka Matsumoto

  • Hi Hirotaka,

    -Mic Bias: it is recommended that you ac couple with a cap to ground, but can be left floating.
    -Unused Analog inputs: it is recommended that you AC couple with a cap to ground, but you can also use a high value resistor to ground. You can read more here: http://e2e.ti.com/support/data_converters/audio_converters/w/design_notes/2810.pcm186x-unused-inputs
    -XO and XI: it is recommended that you ground XI if unused and XO can be left floating.

    Justin

  • Justin san

    Thank you for your reply.
    Ok, we got it.

    Kind regards,

    Hirotaka Matsumoto

  • Justin san

    Thank you for your prompt reply!

    We have one confirmation and question.
    Could you let us know?

    <Confirmation>
    About unused Mic Bias, unused Analog inputs, in case of AC couple with a cap to ground,
    how much of the value should we use?
    We guess that it should be used the same value with other Input pins. 

    <Question>
    About Mic Bias, the datasheet shows followings;

    -9.2.1 PCM1861 with 3.3V AVDD, DVDD and IOVDD, Master Mode with XTAL
    In this case, Mic Bias doesn't connect to any ports(open).

    -9.2.2 PCM1863 with 3.3V AVDD, DVDD , 1.8V IOVDD, BCK Input Slave PLL
    In this case,  Mic Bias connects to AC coupling with ADVV.

    Why does it have difference?
    Or, what kind of the application are these methods(9.2.1 or 9.2.2) used  for?

    Kind regards,

    Hirotaka Matsumoto

  • Hi Hirotaka san,

    So this seems to be a mistake in the data sheet. If you are planning to not use the mic bias pin then you should ground it through a 2.2 uF capacitor.

    Justin
  • Justin san,

    Thank you for your confirmation.

    You said that  this seems to be a mistake in the data sheet.
    So, will you have planning to modify the datasheet in the future? 

    Kind regards

    Hirotaka Matsumoto