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TXS0108E Driver´s Current Capabilities

Haroldo
Intellectual 590 points
Other Parts Discussed in Thread: TXS0108E, SN74AVC8T245

Greetings,

 I´m using an TXS0108E Voltage level translator in the following app:

VccA=2.8V

VccB=3.3V

Max Speed= 115 KBPS

I employ it to interface a 2.8V Logic output UART to a 3.3V USB to SERIAL converter

The driver´s output maximum Load is 1mA at 2.8V, I was told that the auto sensing, bi-directional Voltage Level Translators usually have a

higher driver current demand that Uni-Directional VLT´S.

 Is it OK to interface the TXS0108 with a driver with so low current capability?

  • 0
    TI__Expert 4705 points

    Hi, Haroldo,

    Based on the information you provided here, I could say that it is Ok to use that dirver to drive the TXS0108 with high input.

    But for low input, you did not say the sink current capability for your diver. The 1mA at 2.8V is only the source current capability. please let me know the sink current capability. then I can let you know. the esitmation is while with meeting the requiremnt of the Vil to the TXS0108 (0.15V), the sink current capability of the driver should be more than 0.2mA.  you can check by yourself.

     

    BR

    Junjie

     

  • 0 in reply to Junjie Mai
    Intellectual 590 points

    Hi Junjie,

     Thanks for your prompt response, the sink capability of the driver is 1mA  I believe it is a push-pull output.

    The manufacturer of the device states that it is sensitive to noise and it may latch up if interfaced with components

    that generate spikes and noise such as "switching voltage translators". I´m a bit wary regarding this matter.

    Perhaps the best way to achieve my goal is to try the IBIS model of the part and see how much overshoot I get

    when interfaced with my device. For what I have read the auto-sensing Voltage level translators are more demanding in terms of

    current and generate more noise, maybe that is not the case with the TXS0108.


    What would you recommend? Try another type of converter?

    Regards,

    Haroldo Calvo


  • 0 in reply to Haroldo
    TI__Expert 4705 points

    Hi, Calvo,

    Since I have no idea how sensitive your driver is, I think it is better for you to do some simulation for it. and then find what the noise you want to see. It is better to provide this noise information to the vendor of the driver, and let them help to check it.

    Since it is a UART signal, not a bidirectional signal, you also can check our SN74AVC8T245 part if it is not acceptable for the TXS0108. any further thing, please let me know.

    BR
    Junjie