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TS5A23159: ESD protection.

Anh Nguyen
Prodigy 50 points
Part Number: TS5A23159

Hi everyone.

I have a design use  TS5A23159DGST as attached file. I also use  ESD5581N2T5G to protect I/O pin when I connect them with external peripheral device.

I have tested this PCBA FCT, they are working without any problem, but when we apply weld process after that we test this PCBA FCT again we face with some issue related TS5A23159DGST on my PCBA (ratio 8% in my production), that mean TS5A23159DGST can not switch. I replace the new TS5A23159DGST-> this PCBA passed

I know that:

        - TS5A23159DGST can operate from 1.65V ~ 5.5V in my application I use 3.3V.

        - ESD5581N2T5G have Voltage Reverse:5V, Voltage clamping 12V.

My concern:

       - Whether when we apply weld process, it will generate ESD, this ESD can damage TS5A23159DGST. But I have ESD diode to protect this, so why this can happen?

      - TS5A23159DGST apply with VCC 3.3V, we use ESD diode with Voltage Reverse:5V, Voltage clamping 12V. This diode can protect TS5A23159DGST when this IC operate with VCC:3.3V or not?

      - If we change ESD5581N2T5G to an ESD diode with Voltage Reverse:3.3V whether we can improve this problem.

      - Do you have any advice to improve my situation?

  • 0
    Prodigy 50 points

    Hi. I update my schematic. and weld process picture.

  • 0 in reply to Anh Nguyen
    TI__Genius 14350 points

    Hello Anh,

    From first glance of your question what I believe is going on is during your welding process (where a esd event is occurring) you are accidently exposing the mux to signal on its input pins higher than its supply(input signal > vcc).

    For example the diodes  Reverse voltage(5V) and Clamping voltage(12V) are potential ways the mux can be damaged because those potential voltages are higher than your system VCC of 3.3V. It is recommended in the mux datasheet to not have any signals outside the range of VCC to Grnd put on the device input pins.( If this rule is violated that can damage the mux)

    For your application you need to make sure no signal higher than 3.3V is put on the io pins of the mux.

    I will send this thread to our esd team to see if TI has any solutions for what diode you should use!

    Regards,

    Kameron

  • 0 in reply to Kameron Hill
    Prodigy 50 points

    Hi Kameron.

    Thank for your quick respond.

    I hope to see the solution to prevent this issue as soon as possible, it will help us to resume our production.

    In the short term I can not change the diode in my design, but it can change in the next lot in our production. in this situation if I add more external ESD diode (which TI will suggest me), I think the result is the same with if we replace new ESD diode, what do you think about this?

  • 0 in reply to Anh Nguyen
    TI__Genius 14590 points

    Hi Anh,

    The TS5A23159 can only tolerate -0.5V and +6.5V, so a clamping voltage close to those values is preffered to avoid damage to the mux. 

    Replacing the ESD5581 with a lower working voltage (Vrwm) is definitely a better solution since the clamping voltage will be lower. A uni-direcitonal device will also provide lower clamping voltage for negative ESD events since it breaks down at a lower voltage in the negative region. 

    (Typically devices with a lower Vrwm will have lower clamping voltage compared to devices with higher Vrwm)

     I would recommend our ESD351DPYR here. It's in the same package so it can drop in to the existing footprint on your board. The clamping voltage is much lower and will provide much better protection for the TS5A23159 for positive and negative ESD strikes. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Prodigy 50 points

    Hi Sebastain.

    Thanks for your quick reply.

    I will try your suggestion. I hope that can improve my situation.

    Thanks.