SN74LVT125 Typical Threshold Voltages

Richard Zarr

Intellectual 2880 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?

over 7 years ago

0 Clemens Ladisch over 7 years ago

Guru 259980 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 Richard Zarr over 7 years ago in reply to Clemens Ladisch

TI__Intellectual 2880 points

Thanks, that answers the question...

0 Cory Gregory over 7 years ago 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 Clemens Ladisch over 7 years ago in reply to Cory Gregory

Guru 259980 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 ShreyasRao over 7 years ago in reply to Clemens Ladisch

TI__Guru 56900 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.

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SN74LVT125 Typical Threshold Voltages