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SN54ACT08: SNJ54ACT08J

Part Number: SN54ACT08

I’m looking for a TI technical representative to answer a question on a TI part usage issue.

 

Part is a AND gate device (semiconductor) – 54ACTQ08.

 

We wanted to know the long term effect of a short circuit on it’s output gate.

 

Will it create any kind of thermal overload condition that could translate the fault to the input of the device.

 

We have never experienced any type of fault and would like to find out if it is even possible.

 

Assume part is driving HIGH but shorted to ground.  Will this fault cause a cascade to the input of the device, or will the increased current be handled by the output gate and eventually fuse open?

 

Thank you very much.

 

  • Joseph,

    Unfortunately, this level of analysis did not occur when the device was designed.  Due to the age of the device, it will be somewhat speculation.

    However, I would speculate that a fault on the output would be unlikely to cause the input to short.

    Since this device does not have Ioff, it could cause the input to present a larger load if the internal power bus was compromised from the fault.

    There are a couple people I can check with that may have better insight.  I will check with them and follow back up.

    Regards,

    Wade

  • Joseph,

    I did get a little more feedback.

    a shorted output will usually generate enough current to damage the device, and this can go a few different ways.

    (1)    Most commonly, the output becomes a permanent short to ground or Vcc – this is the case because logic signal drivers don’t usually supply very much current.

    (2)    If enough current is passed through the device (ie several amps), then the device will usually become an open – this can produce a huge amount of heat and desolder the part.

    (3)    I’ve also seen shorts to nearby pins -- ie if the device has pin 7 as an input and pin 8 as an output, and pin 8 is shorted, it might melt internally to  pin 7.

    If this answers your question, please click "This Resolved My Issue"
    Regards,
    Wade