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TXS0108E: the resistance between B7 (pin13) and GND is 11.1129Ω, which is close to short circuit

Expert 1640 points

Replies: 5

Views: 178

Part Number: TXS0108E

Hi 

The customer's board was originally running normally. After restarting, it was found that the card could not be found. After analyzing and testing, we found that the level conversion chip (TXS0108ERGYR) pin is short-circuited. Our test result shows that the resistance between B7 (pin13) and GND is 11.1129Ω, which is close to short circuit
There is an urgent need to understand the mechanism of failure, because this is very important, please try to analyze.
Have you encountered this similar situation before?
Have experience to learn from it, to understand why there is a short circuit between the pin and the ground pin.

Thanks

Elsa

  • Hi,

    I won't be able to analyze with the limited info provided. Could you provide more details like a schematic and scope captures from your testing?

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  • In reply to Dylan Hubbard:

    Hi, Dylan

        Sorry we do not have any scopes , but if you have any advice on figuring this out by using wavescope pls tell me ,and I may use the broken IC do some experiment.

         Below is the schematic of this chip on our board. Thank you for reply!

           

  • In reply to Nessee LI:

    Hi Nessee,

    What all is connected to B7? Heavy loads can cause issues with this device. 

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  • In reply to Dylan Hubbard:

    Hi, Dylan

       This is the topology of our reset system. Pin B7 is driven by MCU or PCIe slot through a logic gate. 

    1.  I  think it's ok because we use MCU GPIO as reset pin in push-pull mode, and other chips connected to MCU reset work normally.

    2.  I suppose this situation with a strong logic gate cannot be called heavy loads . The continuous output current  is ±50mA,through power to GND is ±100mA.

    3.  What kind of issues may occur with heavy loads? 

         Thanks a lot~

  • In reply to Nessee LI:

    Hi Nessee,

    This short can be caused by an EOS event. My question is invalid since the B7 pin is only used with unidirectional signals as an input. Knowing that, we need to isolate the signals going into that pin as it could be an indicator.  LVC has strong drivers which can lead to pretty serious overshoot/undershoot problems. I would use an oscilloscope to see if the signal on B7 (output of the SN74LVC1G08DBVR) has this issue.

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