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Original question:

SN65HVD62EVM　about on board Crystal

SN65HVD63: SN65HVD62 application circuit-crystal

Swetha Samay
Prodigy 210 points
Part Number: SN65HVD63

We wish to use SN65HVD63 with a 8.704MHz crystal which has load capacitance of 40pF unlike the one on eval board which has a load capacitance of 12pF. Do you have any suggested capacitor value to be used for 40pF load capacitance crystal. Please let me know.

Thanks,

Swetha

  • 0
    TI__Mastermind 25705 points

    Swetha,

    The crystal with 40pF load capacitor should work too, as long as it oscillates at the right frequency. The example value in the typical application (page 17) is 40pF in the datasheet.

    BTW, you can find the detailed discussion about the crystal (like parasitic) here.

    www.ti.com/.../swra495g.pdf

    Please let me know if you have more questions.

    Regards,

    Hao

  • 0 in reply to Hao L
    Prodigy 210 points

    On the typical application circuit, are you referring the 40pF to the load capacitance of the crystal or the value of the caps that go from XTAL1/XTAL2 to GND?

    Can 39pF capacitors be used from XTAL1/XTAL2 to GND for the 40pF load capacitance crystal as well?

  • 0 in reply to Swetha Samay
    TI__Mastermind 25705 points

    Yes. I'm sorry for the confusion. My point is C load (CL=39pF/2) from the application note is more than 12pF without considering the stray capacitor. 39pF can be used for 40pF load crystal depending how much ppm offset you can tolerate.

    Regards,

    Hao