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TUSB7320: Correct feedback resistor to use between XI and XO (1M vs 2M)

EeFong Yap
Prodigy 20 points
Part Number: TUSB7320

Hi,

In your datasheet figure 10 Reference design 1, R12 is 1M ohm.

but in page 5, the description for both XI and XO mentioned to use 2Mohm when using a crystal, can you help to clarify the mismatch?

Thanks.

  • 0
    TI__Guru 60870 points

    Hello EeFong,

    The feedback resistor value is not exact, checking with various crystal vendors a value of 1M-5M is acceptable.  

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 20 points

    Ok. I thought below description suggested a fixed 2Mohm resistor.

    Thanks for clarification.

    XI A23 A23 I Crystal input. This terminal is the crystal input for the internal oscillator. The input may alternately be driven by the output of an external oscillator. When using a crystal a 2-MΩ feedback resistor is required between XI and XO.

    XO A22 A22O Crystal output. This terminal is crystal output for the internal oscillator. If XI is driven by an external oscillator this pin may be left unconnected. When using a crystal a 2-MΩ feedback resistor is required between XI and XO