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TLK2711-SP: Question about POR sequense

Go
Genius 4220 points
Part Number: TLK2711-SP

Hi,

 

I'd like to ask about following things,

 

 

1. When we use TLK2711-SP as transmitter only, we should drive LOOPEN and LCKREFN to LOW after Internal POR completed.

How long should we wait before driving LOOPEN and LCKREFN to LOW for appropriate operation?

Is it OK that wait at least 1ms?

2. Question about the timing between VCC/VDDA and GTX_CLK during POR,

Should we supply GTX_CLK before VCC/VDDA reaches 2.375V?

 

3. Is there any problem about the attached POR sequence for appropriate operation?

 

Regards,

 

Go

  • 0
    TI__Guru 62930 points
    Go, I can answer your questions.
    1) yes 1ms is sufficient to complete the reset. (your plot did not include LOOPEN. It should be similar to LCKREFN)
    2) Sequence is not important. What is important, is that all the conditions for POR are met for 1ms.
    Those are as follows:
    VCC/VCCA good
    GTX_CLK on and stable
    ENABLE high
    LCKREFN high
    RXP/N data OR LOOPEN high.

    After the 1ms, LOOPEN can go low and external transmitter will be operational. When LOOPEN asserted, the external TXP/N drivers are disabled.

    Regards,
    Wade
  • 0 in reply to Wade Vonbergen
    Genius 4220 points
    Hi, Wade-san

    Thank you for your comment.

    Regarding my question 3, I'm not sure that the sequence I attached can meet the following criteria you told me.
    Does it meet the criteria?

    And regarding the description in D/S as follows,
    8.3.20 Power-On Reset
    Upon application of minimum valid power and valid GTX_CLK with device enabled (ENABLE = HIGH), the
    TLK2711-SP generates a power-on reset.

    Does it mean LCKREFN and LOOPEN should be high within 1ms after the following condition?
    VCC/VCCA good
    GTX_CLK on and stable
    ENABLE high

    Or does it mean the following conditions should be within 1ms?
    VCC/VCCA good
    GTX_CLK on and stable
    ENABLE high
    LCKREFN high
    RXP/N data OR LOOPEN high.

    Regards,

    Go
  • 0 in reply to Go
    TI__Guru 62930 points
    Your timing diagram did not include LOOPEN. So, it is not sufficient as is.
    If you add LOOPEN going high and low at the same time as LCKREFN, then it would be good.

    Sequence and timing of each of the signals/conditions is not important. What is important is that all the conditions are true for 1ms after powering up.
    So, after all conditions are true, wait 1ms, then bring both LCKREFN and LOOPEN low to commence normal operation.
    Regards,
    Wade