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TMUX1237: Question about EOS(Electrical Overstress)

Chase Jeong
Mastermind 9295 points

Part Number: TMUX1237
Other Parts Discussed in Thread: STRIKE

Dear TI experts,

My customer use TMUX1237DCKR for their product. THe product is in mass production.

And sometimes TMUX1237DCKR is broken by EOS(Electrical Overstress).

Customer did failure analysis, report said that short was observed on multiple pin #2,3,4.

QEM-CCR-2504-01365_TI Quality report_EIPD.PDF 

And to solve this problem I checked the schematic but I could not find nothing special.

Could you guide me about any solution that can prevent this kind of EOS?

Best regards,

Chase

  • 0
    TI__Mastermind 26345 points

    Hello Chase,

    EOS makes sense if they see a short between pins 2,3 and 4 which are VDD, S1, and D. 

    For an EOS event to occur the device has to be exposed to a higher voltage or current on the pins than rated.

    At what supply level are they operating at?
    What is the voltage level present on the I/Os?

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    Mastermind 9295 points

    Dear Nir,

    Thank you for your support.

    Here are the answers from my customer.

    1. Can the customer replicate the EOS event?

    -> Unfortunately no. This failure occurs about 1 time per 3 month.

    This product is installed on bus, there are lots of external equipment. Customer just suspect that this failure is because of the car battery voltage noise or potential difference.

    2. At what supply level are they operating at?

    -> Customer use 5V.

    3. What is the voltage level present on the I/Os?

    -> IO is used for the output of analog video signal. it is 2V level.

    Could you check these information and guide me about adding protection ICs?

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Mastermind 26345 points

    Hello Chase,

    I see, then there is probably some kind of a strike or surge event that damages the mux. 
    A diode might help resolve this issue.

    I looped in the PD team to recommend an appropriate diode.

    Thanks,

    Nir 

  • 0 in reply to Nir Gilgur
    TI__Expert 6210 points

    Hi Chase,

    Unfortunately, the abs max ratings of the 3 pins is very close to the operating voltage. Ex: VDD is 5V and the abs max rating of this pin is 6V. This mean that you would need a diode that breaks down above 5V and clamps below 6V. We do not have this in our portfolio as of now. I would recommend looking at deep snapback diodes which is what you would need to protect lines like these ones.

    Apologies for the inconvenience.

    Bryan