ECL: Why'd they use negative voltages?
in [Design]
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From: krw on 7 Jun 2010 20:54 On Mon, 07 Jun 2010 17:47:12 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 07 Jun 2010 19:43:49 -0500, "krw(a)att.bizzzzzzzzzzzz" ><krw(a)att.bizzzzzzzzzzzz> wrote: > >>On Mon, 7 Jun 2010 17:35:05 -0700, "Joel Koltner" >><zapwireDASHgroups(a)yahoo.com> wrote: >> >>><krw(a)att.bizzzzzzzzzzzz> wrote in message >>>news:4e3r065vr383q2hc9fiuhre2mu9opopbai(a)4ax.com... >>>>>And why 5.2V anyway? (Granted, 5.2V is no stranger than 6.3V filament >>>>>transformers, I suppose...) >>>> >>>> Stack up the voltages (don't forget the AND gate). >>> >>>Purportedly it'll run down to around VCC-VEE = 3V and up to about 8V before >>>you start seeing massive performance differences. 5.2V is certainly pretty >>>close to the center of those two... hmm... I wouldn't be surprised if that's >>>how they came upon it! >> >>No, Jim had the reason above. Try an AND gate at 3V. ;-) > >MC10EP05. > Got a schematic?
From: D Yuniskis on 7 Jun 2010 20:59 Hi Joel, Joel Koltner wrote: > "D Yuniskis" <not.going.to.be(a)seen.com> wrote in message > news:huk3tl$224$1(a)speranza.aioe.org... >> Dunno. But, it was fast and ate gobs of power. In the >> mid 70's I worked on a processor (i.e., what nowadays >> would be a CPU "chip") that drew 100A (MECL III and 10K). >> "Bus bars" for power were 3/4" square copper shafts. > > *Most* impressive. :-) No. Insane. >> If you "slipped" when pulling/installing a chip, the legs >> would vaporize before the power supply would even hiccup. >> (needless to say, you removed all jewelry -- belt buckles, >> eye glasses, rings, etc. -- when working on it) > > --> http://sound.westhost.com/project117.htm (a 1500W audio amplifier, > "It is capable of destroying any loudspeaker connected to it, regardless > of claimed power rating.") :-) Yikes! I used to push 600W when I was in school but never actually *listened* at that level! :> OTOH, I recall a friend designing a 2KV, 2KW supply (at the same time I was working on the aforementioned CPU). He used to joke that he installed switching transistors to protect the *fuses* from blowing (it would vaporize the emitter? pin on the TO-3's). Boss was not amused (I guess they were some pretty expensive switches :> ) I prefer things that don't *bite* when you touch them!
From: krw on 7 Jun 2010 21:00 On Mon, 07 Jun 2010 17:47:28 -0700, D Yuniskis <not.going.to.be(a)seen.com> wrote: >Hi Joel, > >Joel Koltner wrote: >> I realize it was the early '60s and all, but why does ECL generally use >> 0V for VCC and -5.2V for VEE, rather than, oh, say... 5V for VCC and 0V > >You also had a Vbb of around -1.2V (?). Lines were typically terminated >to this. -1.4, IIRC (but maybe not, since it's been almost 25 years since I used MECK 10K). >> for VEE? Something related to how things were done when toobs ruled? (I >> realize that you can almost always run ECL off of 5V/0V -- and >> apparently this was popular practice at one time?) >> >> And why 5.2V anyway? (Granted, 5.2V is no stranger than 6.3V filament >> transformers, I suppose...) > >Dunno. But, it was fast and ate gobs of power. In the >mid 70's I worked on a processor (i.e., what nowadays >would be a CPU "chip") that drew 100A (MECL III and 10K). >"Bus bars" for power were 3/4" square copper shafts. >Instruction cycle time was 8ns. By comparison, I think a >7404 (inverter) takes *7* ns just to change the state of >its output. > >If you "slipped" when pulling/installing a chip, the legs >would vaporize before the power supply would even hiccup. >(needless to say, you removed all jewelry -- belt buckles, >eye glasses, rings, etc. -- when working on it) I worked on a test system that had a 100A -4V *linear* HP supply in it. The thing was the size of a small refrigerator. The other engineer did the 1600 pin pin-driver logic in proprietary ECL (-4V). I did the clock drivers in MECL 10K. I only needed about 50A for the 64 clocks. ;-)
From: Joerg on 7 Jun 2010 21:08 Joel Koltner wrote: > "Joerg" <invalid(a)invalid.invalid> wrote in message > news:875hpjFk48U2(a)mid.individual.net... >> And cars had DC generators. In fact, my old Citroen did as well. >> Crankshaft-driven, no belts in the whole car. > > Seems like a belt is an awfully inexpensive addition for the flexibility > it provide in terms of being able to locate and size your generator > independently of the engine itself, to a large extent! > But it can snap, and it usually does so on a Saturday night in the boonies. About 30 miles past the sign that read "No services next 60 miles". Sez Murphy :-) The one on the Citroen never gave me trouble in all those six years, until the bottom rusted out from underneath the car. Then the whole engine including generator was sold to Norway. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: D Yuniskis on 7 Jun 2010 21:12
krw(a)att.bizzzzzzzzzzzz wrote: > On Mon, 07 Jun 2010 17:47:28 -0700, D Yuniskis <not.going.to.be(a)seen.com> > wrote: > >> Hi Joel, >> >> Joel Koltner wrote: >>> I realize it was the early '60s and all, but why does ECL generally use >>> 0V for VCC and -5.2V for VEE, rather than, oh, say... 5V for VCC and 0V >> You also had a Vbb of around -1.2V (?). Lines were typically terminated >> to this. > > -1.4, IIRC (but maybe not, since it's been almost 25 years since I used MECK > 10K). Dunno. This was 35 years ago. At the time, I didn't realize it wasn't "normal practice" :> >>> for VEE? Something related to how things were done when toobs ruled? (I >>> realize that you can almost always run ECL off of 5V/0V -- and >>> apparently this was popular practice at one time?) >>> >>> And why 5.2V anyway? (Granted, 5.2V is no stranger than 6.3V filament >>> transformers, I suppose...) >> Dunno. But, it was fast and ate gobs of power. In the >> mid 70's I worked on a processor (i.e., what nowadays >> would be a CPU "chip") that drew 100A (MECL III and 10K). >> "Bus bars" for power were 3/4" square copper shafts. >> Instruction cycle time was 8ns. By comparison, I think a >> 7404 (inverter) takes *7* ns just to change the state of >> its output. >> >> If you "slipped" when pulling/installing a chip, the legs >> would vaporize before the power supply would even hiccup. >> (needless to say, you removed all jewelry -- belt buckles, >> eye glasses, rings, etc. -- when working on it) > > I worked on a test system that had a 100A -4V *linear* HP supply in it. The The Vbb supply was a *shunt* regulator. A bunch of Lambda power supplies driving a pair of *big* diodes "selected at test". A colossal waste of power. > thing was the size of a small refrigerator. The other engineer did the 1600 > pin pin-driver logic in proprietary ECL (-4V). I did the clock drivers in > MECL 10K. I only needed about 50A for the 64 clocks. ;-) This was the brains of a "600-pin tester". Programmable power supplies to the UUT. Programmable thresholds for the input comparators. 1ns timing resolution. It was just "insane". |