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UCC2897A: If the SYNC pin is not used, what is the effect of noise on that pin?

Kaji@PAN
Mastermind 7825 points
Part Number: UCC2897A


Hi,

I am considering using UCC2897A device.
If you do not use the SYNC pin, it is recommended to open this pin in the data sheet. The reason is that this pin is bi-directional.
However, when considering noise such as lightning surge and static electricity, I think that fixing this pin is safe.
Since there is no description of whether to pull up or pull down in the internal block diagram, I would like to know the internal configuration of this pin.
Fixing to H is prohibited in the data sheet.
Is it possible to fix to L?
Best regards,
  • 0
    TI__Mastermind 34465 points
    Hello Kaji@PAN,
    Have you done any surge testing or ESD testing and found that this is an issue ?
    The UCC2897A has been used in multiple product designs and noise pickup on the SYNC pin has never been a problem.
    Can you show the results of your tests ?

    Regards
    John
  • 0 in reply to John Griffin1
    Mastermind 7825 points
    Thank you for your reply.

    I am still creating a circuit diagram. Evaluation of the board has not been done yet.
    Since the SYNC pin is an input pin, I think that it is natural to worry about the influence of noise.
    I understood that there was no problem so far.
    However, I am glad that you will tell us whether the device is actually structurally less sensitive to noise.
    Best regards,
  • 0 in reply to Kaji@PAN
    TI__Mastermind 34465 points
    Hi Kaji@PAN,
    Yes you are correct.
    If a synchronization feature is not required in your design then you should ensure SYNC is not connected.
    Regards
    John
  • 0 in reply to John Griffin1
    Mastermind 7825 points
    Thank you for your reply.
    I confirmed the contents on the datasheet SYNC pin.
    When the SYNC pin is open, has I understood that the waveform of the frequency of the internal oscillator is output?
    Since the waveform of the internal oscillator is output, do you mean that you need to open the pin when not using the SYNC pin?
    Returning to the first question, when the SYNC pin is open and the waveform of the internal oscillator is output, does it need to consider the influence of external noise?
    Best regards,
  • 0 in reply to Kaji@PAN
    TI__Mastermind 34465 points
    Hi Kaji@PAN,
    Yes you are correct.
    Leave the pin open/ not connected if you do not require synchronization.
    Regards
    John