ECL: Why'd they use negative voltages?
in [Design]
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From: D Yuniskis on 7 Jun 2010 22:52 Hi Vladimir, Vladimir Vassilevsky wrote: > D Yuniskis wrote: >> Joel Koltner wrote: >> >>> "Vladimir Vassilevsky" <nospam(a)nowhere.com> wrote in message >>> news:26GdnUsFmvX4PZDRnZ2dnUVZ_vadnZ2d(a)giganews.com... >>> >>>> Joel Koltner wrote: >>>> >>>>> --> 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.") :-) >>>> >>>> Pathetic :))))) >>>> Here is 10kW audio amplifier. Yes, 10kW true RMS sustained >>>> sinusoidal power. >>> >>> One has to wonder what sort of speaker systems are used with such an >>> amplifier (10kW) if 1.5kW is purportedly enough to kill any >>> individual speaker -- must be quite the array! > > The recomended system is 4 x 18' woofers. > >> My "home speakers" could suck down 600W (each). They were 4 ft >> wide, 3.5 deep and 6 ft tall. They weighed 1200 pounds. The >> neighbors would visit and ask, "And how are the *children* today?" > > I have some doubts. The actual impedance of the speakers is usually much > higher then rated resistance. A good big loudspeaker can dissipate few > hundred W of sustained active power. The mechanical damage of the > speakers (due to the material fatigue) is big problem at those power > levels also. Each cabinet had 4x15's, 9x5's and 9x2's. Cabinet walls were two inches thick (plywood + particle board laminated together). Screws every 3" (grid). I think there were 60 pounds of screws in each cabinet -- or, perhaps that was per "half cabinet"? (my first speakers taught me that doors aren't as wide as you would like them to be! :< So I cut the cabinets in half to make it possible to get them in and out of buildings! One of my first cabinets still sits in my parents' basement as it wouldn't fit through the upstairs doorway) Somewhere I have photos of me *inside* one of the half-cabinets. And sitting *atop* one of my "first" cabinets (they were much smaller -- 4 ft tall, 3 ft wide/deep)
From: Jim Thompson on 7 Jun 2010 23:33 On Mon, 07 Jun 2010 17:01:03 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >On Mon, 7 Jun 2010 16:56:24 -0700, "Joel Koltner" ><zapwireDASHgroups(a)yahoo.com> 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 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...) >> >>---Joel > >Noise immunity is better with 0/-5.2V > >I was there when they (Narud, Seelbach, Philips, et al) did that. > > ...Jim Thompson See.... http://www.computerhistory.org/semiconductor/timeline/1965-Custom.html ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: krw on 7 Jun 2010 23:39 On Mon, 07 Jun 2010 18:21:55 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 07 Jun 2010 19:54:48 -0500, "krw(a)att.bizzzzzzzzzzzz" ><krw(a)att.bizzzzzzzzzzzz> wrote: > >>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? > >People used to publish schematics of their chips, or at least >functional schematics. No more. > >The EPs are SiGe, I think. Ok, that makes sense.
From: krw on 7 Jun 2010 23:42 On Mon, 07 Jun 2010 18:24:48 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 07 Jun 2010 17:54:10 -0700, Joerg <invalid(a)invalid.invalid> >wrote: > >>Joel Koltner wrote: >>> Thanks John, that's quite informative. >>> >>> "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>> message news:di3r0613v9lkk2p8dq06snde2hgopt87fr(a)4ax.com... >>>> Newer stuff, like EclipsLite, works at 3.3 volts, and some at 2.5. I >>>> do mixed-mode PECL and cmos/FPGAs off a +3.3 volt supply. >>> >>> That's kinda what prompted the question -- Joerg has been pointing me at >>> some of the high-speed logic from the likes of Micrel, and I was reading >>> up some in the old MECL System Design Handbook so that I hopefully won't >>> embarrass myself too badly when I go to use some of it. :-) >>> >> >>If you have the old MECL databooks treasure them, don't let them end up >>in the recycling. Both Motorola and Fairchild did a most excellent job >>explaining stuff in there and I assume many of the authors are no longer >>with us on earth. >> >>If you do a good job bypassing the supply and keeping leads short there >>isn't much that can go wrong. Except for one thing: Some series have >>only half the logic swing and that almost bit me once. > >Another gotcha: some parts really don't like having their inputs >pulled all the way up to Vcc. So you have to make a logic "1", a >junction drop down maybe, and pipe that all over the place. Inverters don't, at least if you want a valid output level. Never had any trouble with non-inverting stages.
From: John Larkin on 7 Jun 2010 23:44
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. Vbb is generated in some chips as the reference switch level for differential inputs, usually 1.35 volts below Vcc. The on-chip Vbb supplies are usually wimpy, too weak and at the wrong voltage for terminations. The "standard" ECL termination is usually 50 ohms to -2 volts. Really short runs can be unterminated, but still need a pulldown; a couple hundred ohms to -5 will usually do. You can do cool delay and one-shot things with ECL by adding caps and weak pulldowns to outputs. John |