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SN74LV4052A-Q1: The impact of leakage current to Y0

wang wan
Prodigy 210 points
Part Number: SN74LV4052A-Q1
Other Parts Discussed in Thread: TS3A5017-Q1

Tool/software:

Hi,  I want to know the impact of the condition shown below:

VCC=0V & input leakage current of Y0=100uA

Will it damage the chip or make the chip work abnormally when VCC is pulled high?

Thanks!

  • 0
    Guru 311870 points

    The Y0 pin has a clamping diode to VCC. If the diode current is not limited, it might damage the device. A current flowing into VCC can (partially) power up the switch itself (below 1 V, correct operation is not guaranteed) and any other devices connected to VCC.

    In general, you should either

    • keep the switch powered at all times (pull INH high to disable all I/Os), or
    • use a switch with powered-off protection like the TS3A5017-Q1.
  • 0 in reply to Clemens Ladisch
    Prodigy 210 points

    What’s the current limit value of the clamping diode? 

  • 0 in reply to wang wan
    Prodigy 210 points

    Oh I see. It's about 50mA. So 100uA won't damage the chip, right? And I measured VCC, it is 0.5mV.  It seems that it doesn't power up the switch.

  • +1 in reply to wang wan
    TI__Mastermind 22950 points

    Hello Wang,

    In a scenario where the voltage on a io pin like Y0 exceeds the supply voltage by 0.5V to 0.7V the esd diode inside of this device would activate.

    If you limit the current to below 50mA(100uA in your scenario) then the device and its internal esd diode path should not sustain permanent damage and should be fine for future operation, however its future operation is not guaranteed 

    Check out this FAQ that explains more.

    However if you would like to use a simpler solution like the ones Clemens pointed out earlier those will also work.

    Regards,

    Kameron