3 ms·
What's DEFL - Diode Emitter Follower Logic, suppose it's IBM's name for ECL? Do we have examples of these circuits being used in critical circuits in mainframes
by yholio 6y ago
What's DEFL - Diode Emitter Follower Logic, suppose it's IBM's name for ECL? Do we have examples of these circuits being used in critical circuits in mainframes of the 60s?
I can't imagine a logic circuit of that era that was technically capable of being clocked at 100Mhz, 30 years before these frequencies became the norm.
- kens 6y agoI've looked, but I can't find anything more about DEFL. (The table says it was used in certain serial numbers of the core memory for the Stretch computer, so it seems rather obscure.) Based on the speed, it's plausible that it is a type of ECL, but I don't know where the diodes would fit in. IBM had other names such as current-steering logic for ECL. Keep in mind that the 10ns speed doesn't mean you can run at 100 Mhz, since there are likely to be multiple levels of logic, as well as other delays. But it's still pretty fast.
- kens 6y agoI found an IBM patent for high-speed logic using diodes and an emitter-follower. I don't know if this is "Diode Emitter Follower Logic" but it kind of matches the name. https://patents.google.com/patent/US3050641A/ https://patents.google.com/patent/US3050641A/