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TUSB2046B - Required clock input accuracy

Kawai
Guru 19785 points
Other Parts Discussed in Thread: TUSB2046B

Hello Team,

Please allow me to confirm about the clock input for TUSB2046B.

Q1) What is the required accuracy for 6MHz crystal input ?

Q2) I believe you could use 48MHz crystal oscillator instead of 6MHz crystal. Customer will use +/-100ppm, does this meet the required spec  for the device ?

Best Regards,

Kawai

  • 0
    TI__Mastermind 18655 points
    Hello Kawai,
    I will check if there is any restriction for the crystal.
    We have used and tested Fox Electronics HC49U. Apart from that crystal we haven’t tried any other ones. While the recommended to use 30ppm crystal at 25deg C, it’s ok to use 50ppm crystal but make sure the load capacitance is 20pF and the other two capacitors C1 and C2 are 33pF.
    Regards
  • 0 in reply to Joel Jimenez0
    Guru 19785 points
    Hello Joel-san,

    Thank you for your support. Please let us know the restrictions.
    Could you please also give us the information and restrictions using crystal oscillator device ?

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Mastermind 18655 points
    Hello Kawai,

    As the datasheet recommends,t he characteristics for the crystal include a load capacitance (CL) of 20 pF, maximum shunt capacitance (Co) of 7 pF, and the maximum ESR of 50 Ω.

    These are some features of the crystal that used in our EVM:

    Frequency Tolerance @25°C ±20 or ± 30 ppm
    Temperature Stability ±30 or ± 50 ppm
    Load capacitance 8pF to 32pF or series

    Regards
  • 0 in reply to Joel Jimenez0
    Guru 19785 points

    Hello Joel-san,

    Thank you for the crystal information. We will ask customer to use the crystal which has same or better performance on the EVM.

    How about my second question ? Can our customer use 48MHz +/-100ppm XO (Crystal Oscillator device) ?

    > Q2) I believe you could use 48MHz crystal oscillator(XO) instead of 6MHz crystal. Customer will use +/-100ppm, does this meet the required spec for the device ?

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Mastermind 18655 points
    Hello Kawai-san,
    Yes, the TUSB2046 has 48Mhz oscillator support. We normally recommend that reference clock should have a ±100PPM or better frequency stability and have less than 50-ps absolute peak to peak jitter.
    Regards,
    Joel
  • 0 in reply to Joel Jimenez0
    Guru 19785 points
    Hello Joel-san,

    Thank you for the information.

    Best Regards,
    Kawai