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SN74LVT125 Typical Threshold Voltages

Richard Zarr
Intellectual 2850 points
Other Parts Discussed in Thread: SN74LVT125

Is this information available for the SN74LVT125?

 

1.       What is the typical threshold voltage between the 0.8 and 2 V switching levels?

2.       What are the variations with temperature?

  • 0
    Guru 243910 points

    The typical threshold for all TTL-level inputs is about 1.5 V.

    According to figure 5 of SCEA010, the threshold of LVT inputs (both style A and B) is not really affected by high temperatures:

  • 0 in reply to Clemens Ladisch
    TI__Intellectual 2850 points

    Thanks, that answers the question...

  • 0 in reply to Clemens Ladisch
    Prodigy 10 points
    Hi Clemens,

    The switching level appears relatively similar at 25C and 85C. Is the same true for low temperatures (-10C, -20C, -30C, -40C)? We understand this switching level can’t be (and shouldn’t be) used as a guaranteed level since between 0.8V and 2.0V is in an unknown input voltage range. We’re really just looking for additional information to help us better understand a design flaw (and its potential impact) in a current design.

    Thanks,
    Cory
  • 0 in reply to Cory Gregory
    Guru 243910 points

    I have no clue; the information above is what I found in TI publications.

    You could extrapolate and assume that lower temperatures don't change the switching level either.

    Or fetch a fridge and start measuring …

  • 0 in reply to Clemens Ladisch
    TI__Guru 56070 points
    Since this is not a Schmitt trigger device , the threshold voltage levels wont be specified on the datasheet . There are range of min and max for the Vt+ and Vt- within which the switching is guaranteed to happen however, this cannot be guaranteed to one point over all the device produced .
    As long as Vih is above 2V, and Vil is <0.8V , switching is guaranteed.
    saying that , Vih / vil levels will have some guardband in them to have the extra cushion to guarantee on the datasheet and I would believe 1.5V will be good across temp.