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TLK110 : rise time of VDD

Other Parts Discussed in Thread: TPS650250, TLK110

Dear specialist.

Our customer refer "TLK1XX Design and Layout Guide (SLVA531A)".
This application note describe about rise time of VDD that should be typically 500us.

They are also considering TPS650250 that has internal soft start that value is typ 750us.

Could you advise whether there are any issues or not ?

Best regards.

  • A 750us power supply ramp should not be an issue.

    Patrick

  • Dear Patrick

    Thank you for your quick response.
    Our customer has additional questions.

    Could you provide max / min cvalue of VDD ramp time?
    If not , please let me know what should they care about how to design power supply to VDD.

    Although EVMs which are ICEv2 and TLK110EVM are used TPS75433 or TPS78633 , there LDOs are able to recommended to power supply to VDD ?

    Best regards.

  • Hi,

    there is no minimum rise time spec limitation for the VDD. any fast transient power supply (up to couple of ms rise time) will be sufficient. you can also use the LDO's found in the TLK110EVM.

    Thanks,

    Aviad

  • Dear specialist

    Our customer hope to have TI check about TPS650250 + TLK110 waveform of rise time.
    Could you support customer's request?

    (Test condition)
    Measurement point VDD-IO(32pin) - IOGND(35pin)

    TLK110 Operation condition : Single Supply , Supply voltage 3.3V

    TPS650250 Operation condition : Output VDCDC1 , 3.3V fixed output (DEFDCDC1 pulled High)

    (Question)
    Our customer measured the rise time up time for TLK110 as above condition.
    They have concerned about "The rise time time of the VDD should be typically 500us" mentioned TLK1xx Design and Layout Guide.

    Although their rise time is 720us,are there any issue waveform as follow ?

    Best regards

     

  • Alpha,

    I do not see any issues with the power supply rise time shown in the waveform.  As noted in the 500us is a typical rise time.  As noted in the previous post, a rise time of a couple milliseconds should be OK.  The 720us rise time you have shown is within this range.  The shape of the supply rise also looks good.  It is a very smooth, linear rise time.

    Patrick

  • Dear Patrick

    Our customer would like to make sure why application note describes rise time 500us although your answer is "a rise time of a couple milliseconds should be OK".

    What should customer consider at power up ?

    Best regards.

  • Dear Patrick

    Could you advise about the above?

    Best regards