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Original question:

SN65DSI83: DSI to LVDS with FPD-Link

DS90UB927Q-Q1: +/-2KV ESD, Screen flick

Qianqian
Genius 5010 points
Part Number: DS90UB927Q-Q1
Other Parts Discussed in Thread: STRIKE

Dear TI Experts,

   I am now using DS90UB926 with DS90UB927.

 +/-2KV ESD will  influence DS90UB927, which lead to the screen flick

I'd like to know how to fix it,here is the sch

  • 0
    TI__Mastermind 30515 points

    hello,

    regarding your ESD test result, please understand this issue from the system-level viewpoint. generally, if the ESD noise is injected into ub927/ub928's high speed serial diff. pairs, the high speed signal is easily impacted by this, which maybe results into flicker. also, if the ESD noise is injected into the panel side, this would result into flicker as well. so, pls check it from system level:

    1. identify which section is the impacted by ESD strike?

    a. ub927/ub928 link?

    b. ub928-> panel link?

    you can use the pattern test to isolate it.

    2. for ub927, generally in the sch. design, the CMC and ESD device in FPD-Link channel would be helpful to bypass the ESD noise.

    3. please make sure that the cable has good shielding performance

    4. pls try to provide good grounding skills in your board design, you need have continuous GND referred to high speed signal and power supply

    5. power supply rejection, pls use the recommended filtering design in ub927 d/s

    6.  if possible, pls use good shielding skills for ESD design

    best regards,

    Steven

  • 0 in reply to Steven(Shenzhen) Shi
    Genius 5010 points

    Dear Steven

    DS90UB927 pattern test,   10KV ESD Air Discharge  will  also influence DS90UB927, which lead to the screen flick

  • 0 in reply to Qianqian
    Genius 5010 points

    Dear Steven

      We found that when we remove the 0.1uF capacitor of the DS90UB926 side, the esd test will be much better, the screem is not flick

    I'd like to know what's the real function of this capacitor and can we remove it?





  • 0 in reply to Qianqian
    TI__Mastermind 30515 points

    Your result surprised me.

    The ac coupling cap. is used to protect the receiver side due to hotswap. From the ESD test viewpoint, this 0.1uf  cap. doesn't impact the esd performance as ESD is high freq. transient energy which would be coupled by this cap. 

    regards,

    Steven