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TS5A21366: voltage check

Shu-Cheng LIN
Guru 11785 points
Part Number: TS5A21366
Other Parts Discussed in Thread: TCA9800, TCA9406, TXS0102

Hi Sirs,

Sorry to bother you.

We would like to use TS5A21366 on I2C

If the COM side have PU to 1.8v, NO side have PU to 3.3v.  VCC is 3.3v.

Have any risk on our design?

On this application, if IN pin is high, how about COM side voltage? 1.8v or 3.3v?

Thanks!!

  • 0
    TI__Expert 5660 points

    Hello,

    Thanks for posting to E2E. I would like to better understand your system. Could you send a block diagram or schematic?

    We typically do not advise PU on each side to different voltages. When the switch is conducting, this could consume a lot of current. You will want to make sure that this current in your system is within the current ratings for the part, otherwise this may cause damage to the device.

    Have you thought about using a level shifting switch?

    Regards,

    Kate

  • 0
    Guru 242930 points

    When the switch is on and the signal level is high, a current will flow through both resistors, and the voltage at the switch is somewhere between the two supplies. This is probably not what you want.

    A proper I²C level shifter passes current only when the signal is low. Check out devices like the TXS0102/TCA9406 or TCA9800.

  • 0 in reply to Clemens Ladisch
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    So, could we use same voltage source on TXS0102, TCA9800?

    Because actually we only have one power source (3.3v) now that why we survey switch solution.

    If couldn't, have other suitable solution can share for us?

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Expert 5660 points

    Hello,

    I would like to better understand your system to help find a solution for you. Could you send a block diagram or schematic?

    Switches act as a low-impedance "short" when the channel is "ON". So, the voltage at the input will be the same as the voltage at the output. Would you like for the voltages to be different at the input and output of a switch? We do have a few switches & multiplexers that are capable of "signal path translation".

    Let me know what you need the device to do and I can help find a solution for you!

    Thanks,
    Kate