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Original question:

DS90UB913A-Q1: Supply voltage(1.8V), external oscillator

DS90UB913A-Q1: questions for Clock

Yusuke Mukuno
Expert 7395 points

Part Number: DS90UB913A-Q1

Hi,

My customer have some questions about clock of DS90UB913A-Q1.

Could you please check my understanding?

Q1. How can I synchronize with the deserializer?

 (My understanding) DS90UB913A have PLL for synchronizing with the deserializer. Is it correct?

 
Q2. Is the initial setting done from the deserializer?

 (My understanding) It should be done from deserializer. Also, OSC is in camera side, how does the clocking for initial setting work?


Q3.Can a crystal oscillator be used for the external oscillator?

 (My understanding) They can use the crystal oscillator. is it correct? Do you have any recommended oscillator?


Q4. If the deserializer has a high-precision clock, is it unnecessary for the camera?

 (My understanding) No. they should select the one of the following options. Is it correct?

By the way, they have an other question for harness requirement.

Q5. Could you please let me know about the define the maximum loss S21 (dB) allowed in the harness?

Customer want get the data for until 2GHz. They found the data for until 700MHz in the following apps note.

Cable Requirements for the DS90UB913A & DS90UB914A snla229

Thanks,

Muk

  • 0
    TI__Guru** 103215 points

    Hello Yusuke,

    Thanks for reaching out. I'll answer each question in order:

    1. Synchronization between SER and DES is done using a bidirectional control channel. It is not actually synchronous in this case between 913A and the DES since the forward and back channels run at different rates. You can find more info about this by watching our TIPL video here: https://training.ti.com/ti-precision-labs-what-is-fpd-link?context=1139747-1138099-1139854-1139837

    2. Option 2 is really the same as option 1 in terms of the bidirectional control channel. The only difference is in what clock source is used to generate the forward channel signaling rate from 913A. The DES can communicate with the SER and the imager using the control channel 

    3. A crystal oscillator can be used for the external oscillator and you must follow the datasheet recommendations to select one with low jitter. Please see datasheet page 11 for details on the requirements. The frequency must be selected based off the desired PCLK for the imager which is being used. You can find details on that in section 8.4.1

    4. For 913A, the reference clock source must always be local. (either from the imager or from a local oscillator. Only our newer 953/935 products can accept the REFCLK from the remote DES and operate without a local clock source

    5. 913A does not have any requirements for the S21 beyond 700MHz because it does not operate at forward channel frequency higher than 1.4Gbps (700MHz). Again, the TIPL video has some information on this 

    Best Regards,

    Casey