But HOW did it get there !-)
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |
It's just zero. But more interesting, how much current will it put into a red LED in the pullup direction?
John
Too bad they don't promote some of those characteristics!
Too bad, excessively-poor engineering that way, in IMHO. Datasheets will NEVER specify every damn thing, they simply cannot. Period. Engineers have to take over. I recognize that in a committee meeting somebody can say this or that isn't specified, but at some point the true stupidity has to be stomped out and eradicated, otherwise nothing useful will get done.
Not the case here.
No, no no. The Cross-conduction currents last really no time and really aren't a problem, given the fast risetimes. The MOSFETs are wired as an inverter, so no extra parts, and no voltage loss. In fact, very nice complementary N- and P-channel single-chip soic-8 MOSFET ICs are plentiful. One IC, that's it. What's not to like?
What? What? What's your problem? Both the NPN pullup and NPN pulldown transistors are paralleled devices active only for output voltages far away from the rails. So the Rds(ON) specs are clearly operative for the P-channel and N-channel MOSFETs, given the 10mA measuring current, while the BJT devices are active for the high currents delivered into a 5-volt output load, i.e., representative of a driven MOSFET in it's Miller-feedback-capacitance gate transition. Clearly they've spent serious silicon on all four devices. That way the part can shine in all its operating regions. This approach is a pretty common trick for MOSFET drivers.
Sorry, missed the forest for the trees. 50 ohm Rds(ON), UP, ain't too shabby... too bad it isn't SPEC'D in a way that Joerg can understand ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
45ohms Rdson _is_ shabby if you have to drive a pulse transformer directly and with about 250mA. The question is how close does the bipolar section get things to the upper rail? There is some kind of charge pump plus a driver up front. But unlike in the good old days no internal schematics are released and every time I called companies on stuff like that they wouldn't release anything. As if the "chip grinders" wouldn't find out anyway if someone really wanted to know. But I am going to try. Again.
There used to be some really good stuff in terms of drivers. The old TI
75xxx series and then TI came out with the TPIC series. Most of that must have been a flash in the pan. Gone. Last month I finally tossed the TPIC databook.-- Regards, Joerg http://www.analogconsultants.com/
Sure, I do that a lot. Using logic chips as amps, for example. But medical is a whole 'nother ballgame. You are always with one foot in court. Has to do with our quite predatory legal ways :-(
Way it goes, someone is going to try their darndest to find just one hair in the soup and then convince a jury that "Aha! Look what this guy has done here", regardless of whether it has any bearing on the issue at hand (power supply fell over and crushed someone's foot, or whatever). But again, maybe ok here, might have to leave that up to the client whether they want to accept it.
C'mon, you remember the old days when every little MOS or BJT was printed in the datasheet in the form of a nice schematic. Nowadays all you get is the output devices and some block diagram. That's it.
It's one thing I'll consider. However, I have been through quite a few last order rounds with complementary devices. For example as pulse drivers for ultrasound beamformers where you have 32, 64 or more of them per system. Quite painful for the purchasing folks. On many projects they require assurances from mfgs as to longevity, in writing. Rarely granted for those parts. Usually goes like "We are sorry to inform you that we are unable to...", a form letter.
-- Regards, Joerg http://www.analogconsultants.com/
I am quite sure National is sitting on a very versatile jewel with the LM5112. Many unexplored uses. If they would hire some of the old folks back out of retirement, have them characterize it thoroughly and then write a _real_ datasheet.
-- Regards, Joerg http://www.analogconsultants.com/
But nowadays a simple function may have 140 transistors inside.
John
As far back as the uA741 schematics have been "representative", as some copy-cats found out the hard way ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
'tis why SPICE was invented. If the mfg cares to release the stuff needed to plug it in. Which these days they often don't ...
-- Regards, Joerg http://www.analogconsultants.com/
Almost ALL Spice models are now "farmed-out" to modeling houses, and are almost always "macro" models rather than device level.
It's not terribly wise to show the competition your actual schematic.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
They must have forgotten to include the smileys and signatures on one of the masks :-)
But seriously, I've used logic chips in unorthodox ways exactly because they released enough information or SPICE sub-circuits that were accurate enough. It has yielded the respective mfgs many years worth of extra sales and profits. Nowadays you often don't even get any SPICE info. A while ago I had a serious issue with a regulator chip. Mfg couldn't explain it and neither could I. Asked for the SPICE file. Nope, can't have that. Asked client for permission and then the mfg whether they could throw our (rather simple) circuit onto SPICE with their model. Nope, won't do that either. -> Kicked it outta there, gone, for good. And there won't be any other business with that series until things and mostly policies change.
-- Regards, Joerg http://www.analogconsultants.com/
I guess there's a market for a system that would automatically create a netlist and device list from microphotographs. ;-)
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
It would probably be ok in this case. But there isn't even that.
It's a balancing act. OTOH they may lose out on business if they decide to be too secretive, and I don't think it would be too difficult to figure it out if someone really wanted to.
-- Regards, Joerg http://www.analogconsultants.com/
You need to exhibit some caution... Spice can (and will) lie to you.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
[snip]
I charge for that ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
It seems strange to me that you won't use a part that doesn't exactly specify your needs, yet you would hang your hat on a Spice simulation.
Like I said before, if I had an unusual need, I'd CHARACTERIZE the part myself.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
Can't they just microscope it? With maybe a little auger sem or ion blasting for details?
John
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