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Original question:

TPS65177: AVDD VGH power down and screen flicker

TXS0108E: If A is always at A high level after power on, and B may be high or low after power on, but A and B never appear at the edge. What is the level of A and B?

user5707026
Genius 3145 points
Part Number: TXS0108E

Hi Engineer,

Txs0108e is a bidirectional level conversion chip.

We know from the data manual that the chip is triggered by the edge.

If A is always at A high level after power on, and B may be high or low after power on, but A and B never appear at the edge. What is the level of A and B?

Thank you!

BRs

Elsa

  • 0
    TI__Guru* 97046 points
    Hi Elsa,
    I do not understand your question.

    You have stated that both Ax and Bx are being driven to specific voltages, but then you ask what the levels of A and B are... they are the levels you forced them to be.

    Also, the TXS0108E is not edge-triggered - it is level-triggered. Note the V_IH and V_IL specifications in the recommneded operating conditions table.
  • 0
    Guru 317370 points
    The TXS hat pull-up resistors, so if any channel is not driven at either A or B side, it will be high. (If either A or B is driven low by an external device, both A and B will be low.)
  • 0 in reply to Clemens Ladisch
    Genius 3145 points
    Hi all,
    Thank you for your answers. It has resolved my issue.
    To add A question:
    I know that TXS0108E has bandwidth requirements. If I input A pulse at port A whose width is less than the width given in the specification (such as less than 16.7 nanoseconds), what will port B output?

    Thank you very much!

    BRs
    Elsa
  • 0 in reply to user5707026
    TI__Guru* 97046 points
    Hi Elsa,
    We do not guarantee operation outside of the datasheet specs.

    That means that we don't test under those conditions, so I can't tell you with any certainty what will happen.

    The fact is that most devices will continue to operate beyond the datasheet specifications - and some of our customers operate them under those conditions. The TXS0108E may continue to operate much faster than what is specified -- or it may not. I would recommend choosing a device that is specified to operate under the conditions your system requires, rather than leaving operation up to chance.

    Also - if your issue is resolved, please click the green button :)