Simple question: has anybody, designing or editing a schematic symbol, ever created a pin of type Open Emitter? What for?
I’m inclined to say that some MOSFET gate-driver chips have open-emitter outputs but at the moment I can’t cite an example.
The venerable (1960’s?) LM311 “high-speed” comparator has both an emitter and a collector output.
Dale
The venerable jelly bean MC34063 switched mode power supply controller has an open emitter output for external FET drive.
Hm, fair enough. I’ve always considered the more specific pin types to be mostly a digital thing - ERC doesn’t really do much useful in the sort of analog circuits you’re talking about, in my experience.
I guess some (thoroughly obsolete) ECL chips could be considered to have open-emitter outputs…
Common cathode 7-segment decoder/drivers such as the MAX7221 are essentially open emitter outputs.
Yes, they are essentially open emitter as well, but hardly obsolete. ECL, PECL, and LVPECL are still widely used.
Where? I’ve seen high-speed comparators with LVPECL-compatible outputs, but I don’t think they were actually ECL devices, and they’re niche enough to be the usual exception to the rule anyway AFAIK.
But what would be the point of having ECL compatible outputs if ECL is “thoroughly obsolete”?
(LV)§ECL is often used in frequency counters, prescalers, clock distribution (>800MHz), even high speed I/O sometimes use ECL due to the noise immunity. There are expansion cards for PC’s with ECL I/O. ECL is simply not obsolete never mind “thoroughly obsolete”.
They were also compatible with the LVDS inputs of the FPGA I was using them with, soooo
LVPECL and LVDS are not compatible, different common mode voltage, different voltage swings, different termination, their voltage ranges don’t even overlap. I don’t suppose you have the number of that comparator?
Anyway, ECL, and it’s derivatives, are not obsolete.
Doesn’t mean a more flexible input can’t be compatible with both.
Nope. It was from Analog Devices, all I remember.