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TXB0108: Level Shifter accidentally driving input signal on "A" side

Part Number: TXB0108
Other Parts Discussed in Thread: TXU0304, TXU0104, TXU0204, SN74AXC4T245,


Is there any the possibility of this Level Shifter(LS) accidentally driving input side of the signals? In our case, LS driving FCU_CFG_DONE/STATUS (where it is supposed to be only behave as a RX and not a TX)? 

Let us know,


  • This is not accidental. The TXB is a bidirectional translator; the output drivers on both sides are always active.

    For unidirectional signals, you should use a fixed-direction or direction-controlled translator like the TXU0104/TXU0204/TXU0304 or SN74AXC4T245.

  • Hi Nikesh,


    Like Clemens said, the TXB0108 is an auto bidirectional voltage translator. The TXB family has weak drive strength to enable the devices to automatically change direction. This means that there is no way to externally specify which direction the signals should go. 


    I recommend using the fixed-direction or direction-controlled translators as Clemens suggested to ensure that the device only translates in one direction.



    Reed Smoot