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TMUX136: Switching time (SEL to output) clarification

Max W
Prodigy 10 points
Part Number: TMUX136

Tool/software:

The datasheet specifies that the switching time from SEL to output is at most 600 ns. Is this just a latency or is there additional time for the outputs to settle? In other words, if COM is connected to A and SEL toggles, will COM stay connected to A until 600 ns pass and then "immediately" connect to B or is there significant (>100 ns) time for COM to be fully connected to B? A TINA sim just shows a 600 ns latency and no additional settling time, but I am not sure if this is a limitation of the model or the actual performance.   

  • 0
    Guru 316860 points

    Figure 7-1 shows how this is measured; it includes the time for the load to be charged through the switch:

  • 0 in reply to Clemens Ladisch
    Prodigy 10 points

    Thanks for the quick reply. I could not find any information in the datasheet about how much of this time is latency versus settling/rise/fall time. For example, does it take 550 ns latency to start switching and then 50 ns for V_A/B to rise/fall/settle or is the breakdown more like 50 ns latency and 550 ns rise/fall/settling time? 

  • 0
    TI__Genius 10552 points

    Hi Max,

    Thanks for reaching out here. So this switching time is somewhat load dependent. If you check the datasheet, this 600ns is based on the conditions in the datasheet. For example, if you have a 50pf load instead of a 5pf load then the switching time will be slower. To answer your question though, there is no defines latency/rise/fall/settling time due to this being load dependent. I would urge to run this via simulation with your specific loading conditions or even get a leadless adapter on TI.com to evaluate the die in real time. 

    Regards,

    Alex

  • 0 in reply to Alex Vish
    Prodigy 10 points

    Thanks for the information. In my TINA sim I see a 600 ns latency and the A/B connection to COM is "immediate", <10 ns settling. I am hesitant to trust this simulation result because I see the model defines an explicit 600 ns delay. Do you know if the model should be accurate for for the rise/settling time in a transient sim?  

  • +1 in reply to Max W
    TI__Genius 10552 points

    Hi Max, 

    The settling time will be load dependent, so the model is likely not completely taking into account an accurate settling time. I would be surprised that in real life the settling time is "immediate." The most accurate settling time would likely need to be modeled in real time. 

    Regards,

    Alex

  • 0 in reply to Alex Vish
    Prodigy 10 points

    Understood, I will buy the adapter to evaluate if we can't find a better switch.