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DS90CR218A: Calculation for tolerate clock frequency

Guru 14330 points

Replies: 7

Views: 171

Part Number: DS90CR218A

Please let me know about calculation for tolerate maximum clock frequency.

Before using DS90CR216A on 36MHz clock.

But latest model is changed 36MHz to 45MHz, DS90CR216A occurring bit error on deserialization.

I want to decide that change DS90CR216A to DS90CR218A became no bit error and the other risks by calculation.

Best regards,

Satoshi

  • Hi Satoshi-san,

    The pixel clock frequency range is determined through design and verification. 45MHz is within the clock frequency range of the DS90CR216A, so if you're seeing bit errors then it may have something to do with your design rather than the part.

    What you have you done so far to debug the issue? Have you checked for signal integrity issues on the clock and data lanes? Is the input clock clean? What is the noise level on the voltage supply?

    Regards,
    I.K.
  • Guru 14330 points

    In reply to I.K. Anyiam:

    I.K-san

    Sorry for my reply delay,
    Now customer is confirming and no issue.
    Thank you very much.

    Best regards,
    Satoshi
  • In reply to I.K. Anyiam:

    Any updates on this issue?

    Regards,
    I.K.
  • Guru 14330 points

    In reply to I.K. Anyiam:

    I.K-san

    Customer information was update, please see below;

    I think that the condition is no-problem, is it correct?

    ------------------------------------------------
    Is the input clock clean?
    ⇒Yes, 45MHz eye pattern is opening larger than 33MHz condition.

    What is the noise level on the voltage supply?
    ⇒28.9mVpp
    ------------------------------------------------

    Best regards,
    Satoshi
  • In reply to Satoshi:

    Hi Satoshi-san,

    I think it would be better if they could get the noise level below 20mVpp. Are they following the decoupling capacitors guidelines on page 10 of the datasheet? But if they are no longer seeing problems then there should be no issues.

    Regards,
    I.K.
  • Guru 14330 points

    In reply to I.K. Anyiam:

    I.K-san

    Customer is changed decoupling capacitor based on the datasheet, but ripple and bit error are occur.
    Now they are considering to change probe and cable for high quality.

    Additional question for combination with DS90CR216A ,
    ①Is there recommended Channel Link 1 repeater IC?
    ②Or, is it possible to communicate DS90CR216A: Rx OUT(CMOS/TTL) to DS90CR215: Tx IN(CMOS/TTL)?

    Best regards,
    Satoshi
  • In reply to Satoshi:

    Hi Satoshi-san,

    Yes it's possible to communicate the DS90CR216A output to the DS90CR215 input. They are directly compatible with each other.

    Regards,
    I.K.

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