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TCA9803: TCA980X I2C buffer input issue

kerr chang
Genius 4075 points
Part Number: TCA9803

Hi Team

            I use TCA9803. Wehn I enable output , My imput have 200ns will be low to GND.

Is it normal ? 

CH2 is output 

CH1 is input

The file is Enable and disable waveform. 

  • 0
    TI__Guru 73331 points
    Hey Kerr,

    Can I see a schematic of this device and what other devices are connect to this device? A block diagram would be helpful.

    Is yellow side A and green Side B or is it opposite?

    Thanks,
    -Bobby
  • 0 in reply to BOBBY
    Genius 4075 points

    Hi Bobby

              The file is schematic. The waveform is on port A ( A side ). I have try to install R343 and R351. It have same issue.

  • 0 in reply to kerr chang
    TI__Guru 73331 points

    Hey Kerr,

    I don't see any issues with your schematic.

    Taking a second look at your waveform pictures, it does look like the yellow waveform is rising a little fast. Is the master driving the yellow waveform open drain? To me it looks like you are using a push pull output.

    Thanks,

    -Bobby

  • 0 in reply to BOBBY
    TI__Guru 73331 points
    Hey Kerr,

    I just checked with one of the design engineers who worked on this device. It looks like this behavior is normal and happens every time A side goes low. Usually though, the master/slave has a low enough VoL that this step isn't seen but if the master/slave has a weaker pull down strength then this step becomes visible.

    There is no danger of the device being damaged (or other devices on the bus) due to this behavior.

    Thanks,
    -Bobby