Actually, the latest version of PSpice has a "smoke" function.
My feeling is, if you need it, you shouldn't be "designing" circuits.
However I have created some esoteric macros to check situations in these recent ultra-small-feature-size processes... like gate SOA ;-)
As for "craters", I've done that many times ;-)
I used to schedule my "explosions" during visits by the sales people... just to keep them the hell away ;-)
...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 |
I love to cook with wine. Sometimes I even put it in the food.
You needed proof?
-- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85.
Michael A. Terrell Central Florida
Well I don't know how it gets any simpler, the Pavg is 1/3 Pmax times the transition to switching period ratio, that's easy to remember. For example, if your SPICE or IBIS modeling indicates that 200ns Tr/Tf are well beyond reality, the gate supply is 15V, and other considerations indicate a Rg=10 ohm is satisfactory, then at F=100KHz you have Pmax=22.5W and Pavg= (1/3)*22.5*(0.4/10)=300mW. Use a 1/2W.
Yes, that's what I had in mind. They're pretty expensive nowadays, but we maintain a full inventory: It's a little surprising how much of my work relies on using them.
Welwyn (now a part of TT electronics, like IRC) also has good pulse-withstanding chip resistors, with good data, as does IRC for that matter.
SFAICT the reduction in MOSFET Ciss for a given current-handling capability amounts to only about a factor two over the years, or maybe a bit more in some special cases. Or are you thinking of a reduction in the gate-drive voltage, with logic-level MOSFETs?
--
Thanks,
- Win
Hello Win,
When I was a kid I scavenged lots of parts, including resistors, from tube sets put out on the curb on bulk waste days. In Europe they used to have those several times a year and it's a field day for "scavengers" like I used to be. Finding a tuner with two AF239 felt like finding a gold nugget. But I also kept all these resistors to this day. In terms of stability not much beats a carbon resistor that has aged for 50 years.
Keeping this old stuff has saved the bacon a few times. When 1.35V mercury batteries were outlawed a Ge diode was about the only device that allowed retooling a camera to 1.55V cells. The alternative would have been an expensive 2-3 point re-alignment at a specialty shop.
Thanks! Good to know.
Actually both. But it was more than that. In the 80's we had to make do with a rather small selection. Very little granularity which meant we often had to select a FET that was way too large but the next smaller one would have caused field failures. HV BJTs weren't an option because they ony made them for specific markets and the video transistors that could stomach the voltage were just a wee bit too slow.
Today's FET selection feels like the all-you-can-eat buffet at Sizzler's.
-- Regards, Joerg http://www.analogconsultants.com
thats all I do. in conjunction with not pushing parts too hard.
Cheers Terry
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