SN74AUP1T32: SN74AUP1T32DCKR and SN74AUP1T02DCKR higher temperature analogs

Hi Michael,

Just to help clarify, are you using these devices for translating voltages?

Hi Dylan,

thank you for your reply. No, the voltages are at 3.3V level everywhere.

Hi Dylan,

thank you for your reply. If so, I'm considering SN74AHC1G32 as the "second best" option. And I have a couple of questions about it:

1. What does "Schmitt trigger action" mean in terms of hysteresis? The tolerance for slow input rise/fall limes is specified in the datasheet, while hysteresis is not. Or specified indirectly, but I missed it.

2. Can you confirm that SN74AHC1G32 can operate in the -40 to 125 C range, as given in the datasheet? Digikey specifies it as -40 to 85 C: https://www.digikey.co.il/products/en?keywords=SN74AHC1G32, I suspect that they are still using some old data. Just to make sure.

Thanks in advance,

Michael

Hi Michael,
(1) Schmitt-trigger action is essentially a marketing term meaning that there's some hysteresis on the input - the datasheet does not specify the amount of hysteresis, and thus it's not guaranteed.

(2) Yes, I can confirm that TI parts are guaranteed to meet TI datasheet specs as found on the latest datasheet available from our website.

I would recommend using a configurable logic gate like SN74LVC1G58. This device has Schmitt-trigger inputs (not Schmitt-trigger action) and can easily be configured as an OR gate. It will not be in the package you requested since it has more pins, but it is the correct function. Otherwise you should add Schmitt-trigger buffers prior to the inputs.

Hi Emrys,

thank you for your reply. It seems like I have missed the whole class of logical gates :-)

Regarding this particular gate, I think this passage from the datasheet is somewhat misleading:

This device functions as an independent gate, but because of Schmitt action, it may have different input threshold levels for positive-going (VT+) and negative-going (VT– ) signals.

First, the "Schmitt action" term is used instead of "Schmitt trigger", despite the fact that the hysteresis is listed among other parameters. So a reader who have been told that "Schmitt action" is not the same thing as "Schmitt trigger" is likely to close the datasheet at once, and to miss a suitable component.

Second, what does it mean it may have different input threshold levels? If it has Schmitt triggers at the inputs, it must have different thresholds for rising and falling signals by definition. And, once again, it follows from the specifications table that the device does have different thresholds for those signals.

I will be grateful for further explanations.

Thanks in advance,

MIchael

Hi Emrys,

Yes, being not only an electronics engineer but also a physicist, I do focus on diction. Moreover, I expect the same of everyone writing scientific and technical texts, where the same words should never be used to mean different things. Simple as that. (Some people prefer not to mention peak-to-peak or RMS when talking about ripples, who cares?)

My point is that if I'm looking for a component that belongs to a certain class, I expect that this fact is mentioned on the first page of the datasheet. This is very useful and user-friendly when you are looking through many datasheets. Of course, it works only if the terms being used are well-defined, which is not the case indeed. I'm still wondering about "may have different thresholds" used instead of just "have different thresholds". This does leave a doubt even after looking at the specifications table. So I have to repeat my question: why the word "may" was used in the part's description? Was it a mistake of the technical writer?

I would like to bring your attention to another datasheet: http://www.ti.com/lit/ds/symlink/sn74lvc1g17.pdf  This is a single non-inverting buffer, isn't it? But look at the section 10, page 11: typical application depicts... an oscillator! The cause is obvious: the writer just used the datasheet of SN74LVC1G14, which is an inverter, as a template. And forgot to change not only "typical application" itself, but also has left multiple occurrences of "SN74LVC1G14" in the document describing SN74LVC1G17!

Another example is here: http://www.ti.com/lit/ds/symlink/lmh6321.pdf  The power supply range of this buffer is given as "5 to +/-15V", while it is clearly seen in the specifications table that at +/-5V the output swing is fairly close to zero. It follows that the power supply range should be given as +/-5 to +/-15V. Once again, there's a contradiction between the text and specifications. It seems that the technical writer uses specification tables prepared by someone else who is much more responsible. Do I have to tell you how much time is wasted before such contradictions are discovered?

This is to illustrate that textual mistakes are of course possible in your datasheets. This is a human thing, it's understandable. I only hope that your comment about diction was a mistake, too. The whole semiconductor industry could not exist without rigorous and unambiguous definitions, boring as they are.

Best regards,

Michael

Thanks for you comments and your suggested fix to our datasheets. I have added them to our errata list and they will eventually be fixed.