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Detailed logic family differences? LS vs HC vs AH etc.
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gorplop:
Hello,

I'm trying to find a document that describes the uses and differences between the logic families (LS, HC, HCT, AC, ACT and so on). Ideally with some rough input/gate schematics, a short note on why it's done this or that way, advantages, tradeoffs etc.

First i found this: http://www.ti.com/lit/sg/sdyu001ab/sdyu001ab.pdf , which seems to be more of a marketing material summary about TI's products. I also found several links like http://www.quadibloc.com/comp/cp01.htm but these generally seem to stop at TTL vs CMOS differences.

After some more searching i gave up and decided to look at the datahseets for the same IC in different families. I chose 74xx04 since that is what I am experimenting with.

The 74LS04 datasheet has a nice single inverter schematic (even three!).

Then I looked at the datasheets for 74HC04 and to my surprise, neither TI nor other 4 vendors (NXP, Phillips, Fairchild, Diodes Inc.) whose datasheets I found decided to not include anything more than a logic symbol :( Same for HCT. At least TI included a nice comparison chart between HC and AHC, which is useful

Then I went onto looking at the 74AC04 datahseet and hit the same wall, there are no schematics, the only drawings are package dimensions (4 pages of package outlines...)

So, does anyone know an application note or other PDF that would outline the general behavior and usage of the various families and could link it? Or even point me in a good search direction?

Cheers

Footnote, I've found several threads on the internet that link TI literature but the links are all dead now, even these from 2018 (!) (way to go TI! :-- )
excitedbox:
I thought I had read somewhere (wikipedia?) that they just denote who manufactured them.not that there is an actual difference. Maybe that is why you can“t find anything about what the differences are?
Zero999:
The 74HC series are buffered,  so the 74HC04 will really be three inverters in series.



Unbuffered parts are often available and are denoted by a U in the part number, i.e. 74HCU04.
Gyro:

--- Quote from: Zero999 on February 17, 2020, 11:45:24 am ---Unbuffered parts are often available and are denoted by a U in the part number, i.e. 74HCU04.

--- End quote ---

Useful for 'semi linear' applications like crystal oscillators.
tggzzz:
"The Art of Electronics" chapter 10 discusses some of the more significant differences.

If you are starting to ask such questions which need detailed and subtle answers, then you are ready for TAoE and will benefit from it in many ways. See many other threads on this forum.
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