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TMS320F280025: VDDIO

Huihuang Chen
Expert 4050 points
Part Number: TMS320F280025


Hi Champ,

may i know the maximum value VDDIO/VDDA 4.6V is constant value or instant value?

when customer do EFT testing , the VDDIO waveform like following:

the maximum value is 4.78V and last around 0.02us , and frequency is 5KHz，may i know this case will have issue or not?

if yes ,what will happen? device will damaged or not?

  • 0
    TI__Mastermind 38830 points

    Hi Johnson,

    It does not really matter that this is constant or instantaneous value.  Operating at the absolute max value MAY cause some reliability issue.

    Regards,

    Joseph 

  • 0 in reply to Joseph Casuga
    TI__Expert 4050 points

    Josepha,

    So above customer cause will have issue or not?

  • 0 in reply to Huihuang Chen
    TI__Mastermind 38830 points

    Johnson,

    If this issue happens a lot, it will damage the device.  You may want to suggest to customer to put a 4V TVS diode on the VDDIO/VDDA  pin to divert the path of the transient if this surge is unavoidable.

    Regards,

    Joseph

  • 0 in reply to Joseph Casuga
    TI__Expert 4050 points

    Josepha,

    Could you  advise how to define " happens a lot" ?

    Another question: if the VDDIO is 4.59V constant value will cause some reliability issue or not?

  • 0 in reply to Huihuang Chen
    TI__Mastermind 38830 points

    Johnson,

    The effect of stress is cumulative so the 0.02us duration where the voltage exceeds the max absolute rating will eventually cause damage to VDDIO.  We do not have the reliability data on how long this could be but designers caution that operating at absolute max rating will cause damage as stated in the specifications.  It does not matter if this is 4.59V as this is still very close to the absolute maximum rating.  Customers have to take this into account when designing their system.

    Regards,

    Joseph

  • 0 in reply to Joseph Casuga
    TI__Expert 4050 points

    Joseph,

    Very samples question , if the VDDIO is 4.50V constant value and never over 4.6V will cause damage to device or not?

  • 0 in reply to Huihuang Chen
    TI__Expert 5710 points

    If 4.5v (or any voltage above the values in Recommended Operating Conditions) is held constantly then the lifetime of the device will be reduced.

    Transient or few-time excursions above Recommended Operating Conditions are acceptable as long as they do not exceed Absolute maximum.

    For Electrically Fast Transient testing, I might suggest two more things in addition to a TVS diode.  First, increase the VDDIO-VSS supply decap to absorb the energy.  Also, for the measurement above, ensure the VSS reference is the local VSS which the C2000 device is connected to, and not any chassis or other system ground.  The 4.6v Absolute maximum is between VDDIO and VSS of the C2000 device.

    Best regards,

    Jason