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DS90UB948-Q1: ESD question

Jiawei Hu1
Expert 5555 points
Part Number: DS90UB948-Q1
Other Parts Discussed in Thread: STRIKE

Hi team,

My customer use 948 in display, and meet esd issue. As you can see in below video, you can see display will flicker in 948 pattern. But not each pattern will have flicker issue. Since I am new to esd, could you kindly give some debug directions to figure out the reason? Thanks!

BR

Jiawei

  • 0
    TI__Mastermind 36950 points

    Hi Jiawei,

    What make to the conclusion that the 948 has an issue? Normally, the ESD test should be performed on the cable, device, and outside of the case. It looks like that you are pointing to the screen and flickering appeared, but this isn't concluded it is from 948. What is the voltage that you are trying to zap on the setup?

    Aaron

  • 0 in reply to Aaron Heng
    TI__Expert 5555 points

    Hi Aaron,

    Thanks for your quickly reply. Customer are not in direct connect with the screen but at a distance and the voltage is 8kV. Just want to check that 948 has issue or not. Could you kindly give some directions to prove 948 is ok? Thanks!

    BR
    Jiawei

  • 0 in reply to Jiawei Hu1
    TI__Mastermind 36950 points

    Hi Jiawei,

    Did you try to zap on cable or even the case whether you see the same issue?

    Aaron

  • 0 in reply to Aaron Heng
    TI__Guru** 103215 points

    Jiawei,

    I would suggest to approach this topic from the opposite direction. Before assuming the 948 has an issue, what evidence points to 948 having a problem compared with any of the other components in this system? There are many elements in this kind of system including power supplies, deserializer, timing controller, and backlight controller. The first thing I would recommend to do is to evaluate if the supply rails going to the various parts on the board are stable or if this test is introducing significant noise/glitches. When the issue happens can it be cleared by a reset of the backlight controller, timing controller, etc.? 

    Basically you need to isolate down to more specific data that tells us what part of the system is actually having an issue before we can conclude it is the deserializer. 

    By the way, I'm not sure what specific standard you are attempting to test here, but typically with ESD compliance testing it is not recommended to hold the gun by hand as this will lead to highly inconsistent results. Most such standards docs call for the gun to be mounted to an actuating arm which can guarantee the same strike position and angle each time. 

    Best Regards,

    Casey