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TDA4vM EVM Crystal (Ver：PROC078E7)

H-J
Intellectual 300 points

Other Parts Discussed in Thread: TDA4VM

Hello，

I have a few of questions about crystal in TDA4vM EVM(Ver：PROC078E7):

1，Why use different load capacitors in the same series of crystal oscillator circuits？

2，Why use different part number of 32.768khz crystal on PMIC and TDA4?

3，What is the parasitic capacitance of each XTAL pin in the TDA4?

Thank you!

  • 0
    TI__Mastermind 42515 points

    Hi,

    for 1. and 2. experts will reply here soon.

    For 3. you can check section "5.11.4.1.1 WKUP_OSC0 Internal Oscillator Clock Source" in the device's datasheet.

    Regards,

    Yordan

  • 0
    TI__Guru 57075 points

    The EVM changed the crystal during development, but failed to change the load capacitors.  An updated schematic/BOM will be available to update them to 12pF for WKUP_OSC0 and 10pF for OSC1.  The small difference is due to the difference in PCB capacitance of the connections.

    The processor and PMIC uses different crystal because each is lifted from other designs.  I've not studied the requirements of the PMIC crystal to determine if same component can be used for both processor and PMIC.  It is certainly possible if device requirements are aligned.

  • 0 in reply to Robert Eschler
    Intellectual 300 points

    I see.

    Thank you very much!