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WEBENCH® Tools/TXS0108E: what are the difference between txs0108e and txb0108e

M sriramdhivakar29
Prodigy 150 points
Part Number: TXS0108E

Tool/software: WEBENCH® Design Tools

Hi,

    what is the difference between txs0108e and txb0108e..

  • 0
    TI__Guru 62050 points
    Sriram,

    Please refer to the FAQ on the difference between TXS TXB autobidirectional devices:
    e2e.ti.com/.../719537
  • 0 in reply to ShreyasRao
    Prodigy 150 points

    Dear ShreyasRao,

                                      Thank you for your kind reply. But according to my design i have some doubt. In the below circuit our mico-processor gpio is connected with A1 to A8 i.e 1V8 level side and corresponding 3V3 device is connected with B1 to B8 i.e 3V3 level side. when we make our Micro-processor gpio high and low at 1V8 level then the 3V3 level side also high and low  showing. But when we make the gpio of microprocessor side i.e example GPIO_96(A2)as low (0V) and short the GPIO_96_3V3 to 3V3. when we read the gpio is not showing high(1) still its show low(0) only.

    since it is bidirectional it must want to read right. but its not reading at all.

                                     

  • 0 in reply to M sriramdhivakar29
    TI__Guru 62050 points
    Hi Sriram,
    I am not sure what are you trying to do.
    Why do you short A side to 0V and short the other side to 3.3V? It will consume current, and the GPIO side may not have enough drive to keep the line at 3.3V.
    If both side are left floating, the respective A/B side ports will be at 1.8 and 3.3V respectively.
  • 0 in reply to ShreyasRao
    Prodigy 150 points

    Hi ShreyasRao,

                                consider A1-A8 is connected with Processor and B1-B8 is floating . Now if i made the processor side gpio as output (Low(0) or high(1)) and give the input to the voltage level shifter as pull-up or pull-down means,Processor state gpio is not changing..

  • 0 in reply to M sriramdhivakar29
    TI__Guru 62050 points
    Sriram,

    I beleive that the OE is high to have the device enabled. Since the TXS has internal pullup, with B1-B8 floating will also be pulled up to the Vccb supply state. The A ports will also be pulled to the respective Vcca port state.
    With the pulldown on the B side, the A side should also follow the B port. This depends on the pulldown resistor used. If you use weak (100K) pulldown, the B side won't be pulled low since the pullup is stronger than that.
    If there is 1K strong pulldown, then it will overide the internal pullup.
    Is this happening on single device or observed on all or many devices?