TCA9517A negative voltage peak / pulse

Hi Viktor,
Thanks for your question. Are you seeing any issues with the device when you disable and take the input voltage negative?

Please see below:

Questions:

-I disable the IC with EN pin, and negative voltage pulse comes to the input ( -0,8V ... -1,5V) , this pulse can appear in the other side?
When you disable the TCA9517A with EN pin, the SCL/SDA I/O go into high-impedance mode. The voltages at the input and output SCL/SDA terminals are isolated.

-The isolation is '100%' if we disable the IC ?
Yes, the isolation is 100%

- Can internal switches open in extraordinary condition ( disabled by EN )? If yes, when?
EN pin controls all of the internal circuitry of TCA9517A. So if the EN pin is LOW, the output drivers are disabled and the I/Os are in high-impedance.

- Can you send me a detailed description / graphs / schematic from the internal isolation switch circuit?
I cannot share the detailed schematic of the Enable circuitry. However, I can give you an overview of the operation of this circuit. The EN pin is a logic input into the digital circuitry which switches the buffer path on/off based on the logic level on EN input.

Thanks,
Rajan

With other IC we meet this effect. Negative impulse on the input can turn on the internal switch and go to the other side and 'destroy' the separeted I2C communication. So it is a very important question in our application.

So now we want to know, TCA9517A has a same behaviour?

Thank you.

Best regards,
Viktor

Viktor,
With the EN pin in LOW state, the output of the TCA9517A gets pulled-up to the VCC through the pull-up resistors. There is no effect on the output. I did a quick measurement in the lab with negative swing on the SCL_in line when EN =LOW, and I see the SCL_out pulled up.

Thanks,
Rajan

Thank you for your quick answer.

Best regards,
Viktor