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  • TI Thinks Resolved

CDCE62002: SPI access timing

Part Number: CDCE62002

Hello.

I have a question about CDCE62002.

Regardless of the presence or absence of REF_CLK, we are planning to do SPI access immediately after Start - Up Time dependencies (Power up) in Datasheet: Figure 27.
For SPI access, we are thinking about setting Buffer select and Loop filter.

Is there no problem?

Thank you.

  • Hello Ishii-san,

    Do I understand you are powering up device from EEPROM, then what to change the loop filter from EEPROM value?
    Can you elaborate more about buffer select?

    73,
    Timothy
  • In reply to Timothy T:

    Hello.

    Thank you for answering.

    We will not use EEPROM.
    Therefore, it does not write to EEPROM.

    We will all write to RAM.

    Therefore, we think that we will change the setting every time at startup from the initial value of the device.

    Thank you.

  • In reply to Masazumi Ishii:

    Hello Ishii-san,

    There is no problem to power up the device then write all the registers.

    73,
    Timothy
  • In reply to Timothy T:

    Hello.

    thank you for your answer.

    Please check again.
    For the contents, please see the attached document

    Thank you.Question.pdf

  • In reply to Masazumi Ishii:

    Hello Ishii-san,

    Thanks for the clarification. That image shows the reference start-up time happening at high limit of the POR reset 2.64 V.

    I recommend waiting for all the voltages to achieve the minimum recommended operational voltage of 3.0 V. Once this occurs, you could start programming registers. However, if you start VCO calibration before the reference start-up time + delay time, the calibration may not be valid and would have to be done again.

    73,
    Timothy

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