Standard Logic Symbols (4xxx, 74xx, 74x1Gxx) Edited, Corrected, Pruned. Free to Use

The default KiCAD standard logic symbol libraries (4xxx, 74xx and 74x1Gxx) are a bit of a mess and have meant wasted time for me.

I few weeks ago I had time to spare and sat down to build my own standard logic libraries. Took some days.

1: the libraries have been pruned of all parts that are obsolete or inactive at the manufacturers.
2: all “alias” devices have been removed.
3: the symbols have been unified, so that gate/buffer/inverter etc. share the same graphics in all three libraries.
4: incorrect symbols have been corrected.
5: inversion/negation conventions are the same for all, and signal names correspond to those from the manufacturer data sheets.
6: Alternate/De Morgan symbols are available for all symbols where relevant.
7: symbol descriptions now have a single nomenclature.
8: all datasheet links have been removed (many were old or wrong). A quick web search works better.
9: all footprint referencs have been removed. Using the latest data sheet is better (and they don’t belong in a symbol library).

The result is three relatively straightforward libraries that are easy to use when designing.
The 74xx library only contains 74HCxx parts, because that’s the basic family. In your schematic, rename to HCT/AC/ACT/VHC etc. as needed. The same for the 74x1Gxx library.

The libraries have “0_” as prefix, this brings them to the top of the list when selecting symbols.

OK, perhaps TL/DR, dunno.

Feel free to use the libraries as you wish, they are attached here.
0_4xxx.kicad_sym (289.8 KB)
0_74xx.kicad_sym (444.8 KB)
0_74xxx1Gyy.kicad_sym (91.7 KB)

Less is More!

8 Likes

Thank you for the 74xx IC libraries. I will really appreciate them when I use these old TTL chips again. Thanks also for the 0_ prefix trick.