You can still get pre-LS TTL as well! Gets a bit warm that stuff.

dboreham · on July 30, 2017

Wow. There wasn't much reason to use that in the 80s once LS and F appeared. Perhaps for Iout(max), which I seem to remember is higher for the non-LS?

cjsuk · on July 31, 2017

Yes fan out is ~25 as opposed to ~10.

Early TTL is still used for building oscillators, timing circuits and monostables because lots of long run products were designed with those in and the LS/HC parts aren't equivalent due to bias current etc.