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TXS0104E

Pradap Raj
Prodigy 130 points
Other Parts Discussed in Thread: TXS0104E, SN74AVC4T245

Hi,

    We are planning to use TXS0104E for SPI bus buffering in our board. This SPI bus is connected to 4 devices after this buffering. Please let me know whether it can drive 4 devices or not? Since SPI bus signals are unidirectional signal, Is it ok to use unidirectional buffer which has high drive if TXS0104E cant drive?

Regards,

Pradap

  • 0
    TI__Genius 9085 points

    The TXS0104E can handle a load of ~100pF. 4 devices should not exceed this load, as long as your trace lengths are not several inches. 

    It would also be acceptable to use a unidirectional buffer.

  • 0 in reply to Hattie
    Prodigy 130 points

    If we use unidirectional buffer,if the Input to the buffer is high impedance, then what will be the state of output ?  Also In TXS0104E , can  unused pins be left open or need any external termination?

  • 0 in reply to Pradap Raj
    TI__Genius 9085 points

    If the GPIO connected to the SN74AVC4T245 (uni-directional/ direction controlled buffer) is high impedance, the output is unpredictable. You could put a pull-up or pull-down resistor on the line to prevent the node from floating.

    The SN74AVCH4T245 has a bus-hold circuit and the output will hold the last value before the input became high-impedance.

    Because the TXS0104 has internal pull-up resistors, the IO pins can be left open.