IBM's LVI (Low-Voltage Inversion Logic)

A project log for Hackaday TTLers

Where DIY DIP/SSI/MSI CPU makers meet and discuss other TLA (three letters acronyms)

yann-guidon-ygdesYann Guidon / YGDES 07/06/2023 at 12:470 Comments

I was looking for Ken Shirriff's reference about the Intel i960 and found that on page 41 of !

The only other reference found on Google is on pages 133-135 of

That's mind-boggling. I have never heard of this or seen it before. It works with identical polarities of transistors, which simplifies the design compared to some types requiring complementary parts (NPN+PNP), lowering the cost.

I'm sure the other TTLers will want to have a try with the types of transistors they have : either 2N2369, or AF240, or just dumb BC548... Of course one must verify that this works with discrete transistors.

NOR2 requires 5 transistors, it's a 2N+1 count so it increases faster than ECL but even a NOR3 is worth the effort. Unlike ECL there is no complementary output though, so certain logic simplifications are not possible... So it's only NOR, like in the old-good-CDC6600. Which raises the question of how to make a suitable DFF.

Time for some Fasltading then ? Sure.

Who knows anything else about this ?