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TCA9539: Maximum allowable rise time for I / O input

kazuo shirota
Prodigy 40 points
Part Number: TCA9539


I have a question about TCA9539RGER. What is the maximum permissible rise and fall time for I / O inputs?

From the data sheet, only the I2C input rise time is listed.
There is no detailed explanation about tr and tf of terminals P00 to P17.

Please also check the reference materials.

  • 0
    TI__Guru* 77981 points

    Hi Kazuo-san,

    Our datasheet doesn't specify a rise/fall time on the inputs of the p-ports because it doesn't have such a requirement. As long as you are within the recommended operating conditions for the device (including the p-ports), there shouldn't be damage to the device as long as conditions are not violated. So very fast rise/fall times should not damage the device. 

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 40 points

    Hi Bobby

    Thanks!
    I want to know that it works when rise very late. (Limitation of rise time)

    from k.shirota

  • 0 in reply to kazuo shirota
    TI__Guru* 77981 points

    Hi Kazuo-san,

    The P-Ports detects lows/highs based on voltage, not slew rates so as long as you are above/below ViH/ViL then it shouldn't be a problem though a slow rise time just means it takes longer for our device to detect it. One thing though, if there is a lot of noise during the rise, I believe you could assert/deassert the INT a few times. The hysteresis on the inputs of the p-ports are a bit low.

    -Bobby