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TCA9800: whether TCA9800 input signal has risks

Frank Xiao
Genius 12055 points
Part Number: TCA9800

Hi team,

My customer is using the TCA9800 now. The yellow one is clock, voltage level is 1.8v.(A side is master, B side is slave, B side is 2.5v). We find the Aside(input from CPU signal has a voltage drop at 500mv voltage level. We want to check the whether it has risks. Thanks.

From  my  point of view, if the voltage drop always below 500mv, it will be fine. But here the voltage jump to 648mv may have risks. But if the Vih and VIL has Hysteresis, it should also have no risks.  Could you please help double check it? Thanks. 

  • 0
    TI__Guru 73271 points

    Hey Frank,

    I'm assuming you have some kind of I2C switch/translator on A side of the device, this is a typical kind of signal we see as an artifact of a pass FET architecture device. 

    This glitch you are seeing looks like its about 2.5ns long, I2C spec has a requirement for a 50ns glitch filter on all slaves so this glitch should not be detected by any slaves that are I2C compliant. This means there should be no risk of this glitch causing any problems for the slaves.

    -Bobby