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ISOW7842: What is the Maximum Input Rise/Fall time for the Inputs?

Part Number: ISOW7842

As the title requests, what is the maximum input rise/fall time for the inputs on the ISOW784* series of parts? I see the typical/maximum output rise time in the datasheet, but cannot seem to find the input rise/fall time limitations.

  • Hi Donald,

    There isn't really a maximum input rise / fall time for the input channels (A, B, C, D) of the ISOW784*. The device can transmit a DC signal (high or low) which is "infinite" rise / fall time I suppose.

    The device is limited in a minimum input rise / fall time sense due to the maximum data rate (100Mbps).

    Does that answer your question? Or did I misunderstand what you are asking?

    Best regards,

    Dan
  • Hi Dan,

    Essentially, what I'm asking is how long an input signal can take to cross the metastable region, in-between "Input Pin Rising Threshold", Vith, and the "Input Pin Falling Threshold", Vitl. Per TI Application Report SCBA004D, a too-slow rise time can result in excessive current being drawn, and is generally undesirable. However, I would like to slow the rise time of my signal as much as practical to reduce radiated EMI.

    It looks like the ISOW784x series may have Schmitt-trigger inputs, eliminating the metastable region, but that feature is not mentioned in the datasheet; it is only implied in the "Pin Configurations and Functions" drawings.

     

  • Hi Donald,

    Sorry for the delay. Yes I can confirm that the inputs have hysteresis and that this should not be an issue with the ISOW784x devices. 

    Best regards, 

    Dan