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TXS0102: VCCA>VCCB

Takashi Yamaguchi
Genius 13280 points
Part Number: TXS0102

Hi team,

My customer is considering to use the TXS0102. Could you please advise to the question below?

According to the app note below, there is internal protection diode between VCCA and VCCB.  Can you tell me the power consumption deadline that causes device damage when VCCA> VCCB?

https://www.ti.com/lit/an/scea060/scea060.pdf

Regards,

Yamaguchi

  • +1
    TI__Mastermind 45635 points

    Hey Yamaguchi,

    It could be in the 50mA range like other current ratings listed in the Abs max table, but I don't have an exact value to provide. I can only advise not using the device with VCCA > VCCB.

  • 0 in reply to Dylan Hubbard
    TI__Genius 13280 points

    HI Dylan-san,

    Thank you for your support. I received additional questions from the customer.

    1. Is the restriction "Not using the device with VCCA > VCCB" a restriction when OE is high? Is there a problem if Vcca > Vccb when OE is Low?(The datasheet states that there are no restrictions on the power supply sequence for Vcca and Vccb.)

    2. On the condition of OE is in Low state:
    When the Vcca and Vccb power supplies are input, will the IO pins on the A and B sides be pulled up to Vcca and Vccb respectively? (I am referring to the diagram on page 2.) https://www.ti.com/lit/an/scea060/scea060.pdf

    In that case, is there a possibility that the behavior will change depending on the large/small relationship between Vcca and Vccb?

    Regards,

    Yamaguchi

  • +1 in reply to Takashi Yamaguchi
    TI__Mastermind 45635 points

    Hey Yamaguchi-san,

    For question 1, it should be fine while OE is low since the device is disabled and not operating. The shouldn't be VCCA > VCCB when the device is enabled and you are trying to pass signals through the device.

    For question 2, since the OE pin is Low the I/O will be disabled and will not track the supply voltage. There could be a brief moment where the you see the I/O voltage track the supply before disabling, but that depends on the sequencing. If the OE pin was tied to VCCA the I/O voltage would track the respective supply voltage due to the pull-ups internal.

  • 0 in reply to Dylan Hubbard
    TI__Genius 13280 points

    HI Dylan-san,

    Thank you for the answer. I explained it to the customer and he understood.

    Regards,

    Yamaguchi