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DS90UB947-Q1: How to pass 8kv Contact Discharge?

Sherry Liang
Genius 10255 points
Part Number: DS90UB947-Q1
Other Parts Discussed in Thread: STRIKE

Dear team,

In our datasheet, our 947 can pass 8kv Contact Discharge(IEC 61000-4-2). But my customer did this 8kv contact discharge ESD test with the 947 board designed by themselves, the screen will be displayed black screen. Removing the test, the display will be displayed normally again. It seems that our 947 can't withstand this test. Do we add additional protect circuit when we do this ESD test? If so, could you please tell me what protect circuit we should add? We need to pass this test now.

Thanks & Best Regards,

Sherry

  • 0
    TI__Guru** 103215 points

    Hello Sherry,

    The ESD ratings in this table are pin level tests, not system level tests. These tests check for the maximum applied strike energy before the part is damaged when the part is in isolation - they do not indicate system level performance while the part is actively running in conjunction with other devices on the board in a full system. In a system level test, the maximum ESD strike voltage before disruption occurs is based on the HW design, where the strike is applied, how well the HW shields the sensitive high speed signals from coupled energy, etc. Adding additional ESD protection externally may help to increase the allowed strike voltage before damage occurs, but it will likely not help to prevent data loss during the strike because the ESD diode protection mechanism pulls the signal to GND in order to shunt energy away from the device. However this also means the data signal is pulled to GND which means some high speed data will be lost. 

    The most effective method to ensure higher system level ESD performance is to ensure that from the HW design/physical perspective, the housing, shielding, and grounding of the board are all designed to shunt aggressor energy away from the high speed signals to begin with.

    Best Regards,

    Casey