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DS90UB953-Q1: Configuration check and the method of diagnostics detection for Clock input

Yusuke Mukuno
Expert 7395 points
Part Number: DS90UB953-Q1

Hi Expert,

My customer have some question for DS90UB953-Q1.

Q1,

Customer is considering the following configuration

- Xtal Oscillator to the imager

- Imager clock out to DS90UB953-Q1 CLKIN (20pin)  

Is it possible? Also, could you please let me know the recommended setting for DS90UB953 mode for in this case?

Q2,

Customer want to monitor the Xtal abnormal condition, like frequency shift, amplitude drop, etc.

Do the DS90UB953 have any function of the diagnostics for clock input?

Can they use the Serializer Status and Monitoring (953 datasheet 8.3.4)?

Can they use the Channel Monitor Loop-Through Output Driver (CMLOUT) (954 datasheet 8.4.10)?

Thanks

Muk

  • 0
    TI__Expert 3390 points

    Hi Yusuke,

    Q1: They could use any clock source as long as it meets the Electrical characteristics defined in the datasheet for the CLKIN pin. If they decide to do this, then the DS90UB953-Q1 needs to be in Non-Sync External Clock mode. If connected to a 954/960, the back channel rate should be switched to 10Mbps. Why do they want to do this? Why not use sync mode? It would help reduce the BOM cost because they can use the REFCLK from the Deserializer.

    Q2: There is no section noted as 8.3.4 in the 953 datasheet. I think you meant 7.3.4, you wouldn't be able to detect amplitude drop, frequency directly in terms of the xtal. What these forward channel and back channel diagnostics would tell you is the behavior of the forward channel and whether there was lock or any back channel errors. However, by just monitoring the registers, you wouldn't be able to say the cause of lock or abnormal conditions is due to the XTAL because there's multiple factors that can influence lock drops or back channel errors. CMLOUT would provide you with an eye diagram of the forward channel. What you could do is try the XTAL and then try some other clock sources and do a comparison of the eye diagram and see if the XTAL is having any negative effect on the eye.

    Regards,

    Mandeep Singh