On Wed, 26 Jun 2013 11:17:22 -0700, Joerg <invalid@invalid.invalid> wrote:>Jim Thompson wrote: >> On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: > >[...] > > >>>> I posted the problem on the LTspice list, but was basically told, >>>> "LTspice, love it or leave it" :-( >>>> >>>> All I've been able to find out is that LTspice encrypted models are >>>> behavioral internally. >>>> >>> They are, mostly. That is the reason why you can simulate switchers so >>> blazingly fast. This does come with pitfalls and (minor) risks but it >>> sure beats non-behavioral sims that take hours. >> >> I've been at this simulation stuff so long, I can recall simulations >> taking DAYS! >> > >Same here. I still have the cloth-covered binders from Microsim. Got >that in 1990, I think. Before that I used ECA224. > > >> But today's simulators (and CPU's) are so much faster... it's rare for >> a complex simulation, at device-level, to take more than 20-30 >> minutes. >> >> Patience is a virtue ;-) >> > >Yeah, in the winter it's ok. But in July/August times it has happened >that too much simulating brought the office temps from 85F to over 90F.You don't have A/C? Admittedly, my office runs about 5�F above the rest of the house, but I can cure that by turning on a squirrel-cage blower sitting in the office doorway ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
8051F020 series, 5V tolerant input schematic?
Started by ●June 25, 2013
Reply by ●June 26, 20132013-06-26
Reply by ●June 26, 20132013-06-26
Jim Thompson wrote:> On Wed, 26 Jun 2013 11:17:22 -0700, Joerg <invalid@invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >> [...] >> >> >>>>> I posted the problem on the LTspice list, but was basically told, >>>>> "LTspice, love it or leave it" :-( >>>>> >>>>> All I've been able to find out is that LTspice encrypted models are >>>>> behavioral internally. >>>>> >>>> They are, mostly. That is the reason why you can simulate switchers so >>>> blazingly fast. This does come with pitfalls and (minor) risks but it >>>> sure beats non-behavioral sims that take hours. >>> I've been at this simulation stuff so long, I can recall simulations >>> taking DAYS! >>> >> Same here. I still have the cloth-covered binders from Microsim. Got >> that in 1990, I think. Before that I used ECA224. >> >> >>> But today's simulators (and CPU's) are so much faster... it's rare for >>> a complex simulation, at device-level, to take more than 20-30 >>> minutes. >>> >>> Patience is a virtue ;-) >>> >> Yeah, in the winter it's ok. But in July/August times it has happened >> that too much simulating brought the office temps from 85F to over 90F. > > You don't have A/C? Admittedly, my office runs about 5�F above the > rest of the house, but I can cure that by turning on a squirrel-cage > blower sitting in the office doorway ;-) >We do have A/C but don't run it. Our power prices have been californicated. One of those stupid super-progressive inverse tier systems where, if you work harder and use more electricity, you get punished :-( The evap cooler doesn't quite reach to this end of the house. Still trying to figure how to mount a 2nd evap unit on the garade, ducting it through there and into the hallway next to the office. That'll be one very complicated duct, and since they don't sell fire-proof flexible material of sufficient diameter I'd get to build all that myself. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 11:24:38 -0700, Joerg <invalid@invalid.invalid> wrote:>Jim Thompson wrote: >> On Wed, 26 Jun 2013 11:17:22 -0700, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>> [...] >>> >>> >>>>>> I posted the problem on the LTspice list, but was basically told, >>>>>> "LTspice, love it or leave it" :-( >>>>>> >>>>>> All I've been able to find out is that LTspice encrypted models are >>>>>> behavioral internally. >>>>>> >>>>> They are, mostly. That is the reason why you can simulate switchers so >>>>> blazingly fast. This does come with pitfalls and (minor) risks but it >>>>> sure beats non-behavioral sims that take hours. >>>> I've been at this simulation stuff so long, I can recall simulations >>>> taking DAYS! >>>> >>> Same here. I still have the cloth-covered binders from Microsim. Got >>> that in 1990, I think. Before that I used ECA224. >>> >>> >>>> But today's simulators (and CPU's) are so much faster... it's rare for >>>> a complex simulation, at device-level, to take more than 20-30 >>>> minutes. >>>> >>>> Patience is a virtue ;-) >>>> >>> Yeah, in the winter it's ok. But in July/August times it has happened >>> that too much simulating brought the office temps from 85F to over 90F. >> >> You don't have A/C? Admittedly, my office runs about 5�F above the >> rest of the house, but I can cure that by turning on a squirrel-cage >> blower sitting in the office doorway ;-) >> > >We do have A/C but don't run it. Our power prices have been >californicated. One of those stupid super-progressive inverse tier >systems where, if you work harder and use more electricity, you get >punished :-( > >The evap cooler doesn't quite reach to this end of the house. Still >trying to figure how to mount a 2nd evap unit on the garade, ducting it >through there and into the hallway next to the office. That'll be one >very complicated duct, and since they don't sell fire-proof flexible >material of sufficient diameter I'd get to build all that myself.Have fun! I did roll my own ductwork at the old house... sheet metal shop in Jr. High School was one of my favorite classes ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> wrote:>Jim Thompson wrote: >> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jim Thompson wrote: > >[...] > > >>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>> ONLY on their web-based simulator. >>>>>>>> >>>>>>> That would be a marketing decision that borders on stupid. >>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>> >>>>>> (I even showed them various posts from this newsgroup complaining >>>>>> about model quality... did no good.) >>>>>> >>>>> Then I assume they'll never understand why, when it comes to performance >>>>> and cost is not a major issue, I always default to LTC and never even >>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>> behavioral models that work in LTSpice and AD does not. >>>>> >>>>> Same with TI. Who in their right mind would install and learn half a >>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>> is the de facto winner, oh well. >>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>> Cadence tool, and most amateur spin-offs. >>>> >>> If you run a complicated switcher non-behavioral (and I had to do that) >>> the sims take forever. For designing SMPS that clearly is not the most >>> efficient method. >>> >>> >>>> Encrypting so a model will run only on the parent tool turns me off. >>> >>> Me, too. >>> >>> >>>> What do you do if you want to mix LT and ADI and TI parts on your >>>> board? You're screwed. >>>> >>> On high end designs I never do that, and there is no need to. You can >>> usually get everything at LTC. Except for some hardcore RF stuff and >>> then that gets simulated separately. >>> >>> If it has to be cheap then no special ICs are used anyhow most of the >>> time. For example, my first mass-produced device with a boost converter >>> revolves around a CD40106 as the "highest-tech" chip. There is no >>> dedicated PWM chip because that would have added at least 10c back in >>> the early 90's. >>> >>> >>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>> customer. Enjoy >:-} >>>> >>> Well, yeah, at some point you have to pick one and run with that. I have >>> made my choice, and that choice is LTC. >> >> "Most" of their stuff is good. I've had a recent situation where an >> encrypted model works just fine on LTspice, but not on a PCB. >> > >Same here, the LT6700 had a glitch on the chip and I was the unfortunate >one who had to discover that the hard way. > > >> The FAE was flummoxed, referred the problem to factory... 4 months >> have passed, no solution. >> > >In my case the LTC design engineers looked at it right away, found out >that it was indeed a bug, fessed up, apologized, rolled up the sleeves >and corrected things. That left a very positive impression with me. > >Over the years I experienced numerous similar situations with other, >larger manufacturers. The classic solution was an attempt to cover it up. > > >> I posted the problem on the LTspice list, but was basically told, >> "LTspice, love it or leave it" :-( >> >> All I've been able to find out is that LTspice encrypted models are >> behavioral internally. >> > >They are, mostly. That is the reason why you can simulate switchers so >blazingly fast. This does come with pitfalls and (minor) risks but it >sure beats non-behavioral sims that take hours.My LT3757 boost sim runs at about 15 PPM of real time. I need seconds of sim to model my product, so I'd get two or three runs per week. And I'd run out of hard drive for the RAW file! I've ordered samples. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 11:34:14 -0700, John Larkin <jlarkin@highlandtechnology.com> wrote:>On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >wrote: > >>Jim Thompson wrote: >>> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >> >>[...] >> >> >>>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>>> ONLY on their web-based simulator. >>>>>>>>> >>>>>>>> That would be a marketing decision that borders on stupid. >>>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>>> >>>>>>> (I even showed them various posts from this newsgroup complaining >>>>>>> about model quality... did no good.) >>>>>>> >>>>>> Then I assume they'll never understand why, when it comes to performance >>>>>> and cost is not a major issue, I always default to LTC and never even >>>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>>> behavioral models that work in LTSpice and AD does not. >>>>>> >>>>>> Same with TI. Who in their right mind would install and learn half a >>>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>>> is the de facto winner, oh well. >>>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>>> Cadence tool, and most amateur spin-offs. >>>>> >>>> If you run a complicated switcher non-behavioral (and I had to do that) >>>> the sims take forever. For designing SMPS that clearly is not the most >>>> efficient method. >>>> >>>> >>>>> Encrypting so a model will run only on the parent tool turns me off. >>>> >>>> Me, too. >>>> >>>> >>>>> What do you do if you want to mix LT and ADI and TI parts on your >>>>> board? You're screwed. >>>>> >>>> On high end designs I never do that, and there is no need to. You can >>>> usually get everything at LTC. Except for some hardcore RF stuff and >>>> then that gets simulated separately. >>>> >>>> If it has to be cheap then no special ICs are used anyhow most of the >>>> time. For example, my first mass-produced device with a boost converter >>>> revolves around a CD40106 as the "highest-tech" chip. There is no >>>> dedicated PWM chip because that would have added at least 10c back in >>>> the early 90's. >>>> >>>> >>>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>>> customer. Enjoy >:-} >>>>> >>>> Well, yeah, at some point you have to pick one and run with that. I have >>>> made my choice, and that choice is LTC. >>> >>> "Most" of their stuff is good. I've had a recent situation where an >>> encrypted model works just fine on LTspice, but not on a PCB. >>> >> >>Same here, the LT6700 had a glitch on the chip and I was the unfortunate >>one who had to discover that the hard way. >> >> >>> The FAE was flummoxed, referred the problem to factory... 4 months >>> have passed, no solution. >>> >> >>In my case the LTC design engineers looked at it right away, found out >>that it was indeed a bug, fessed up, apologized, rolled up the sleeves >>and corrected things. That left a very positive impression with me. >> >>Over the years I experienced numerous similar situations with other, >>larger manufacturers. The classic solution was an attempt to cover it up. >> >> >>> I posted the problem on the LTspice list, but was basically told, >>> "LTspice, love it or leave it" :-( >>> >>> All I've been able to find out is that LTspice encrypted models are >>> behavioral internally. >>> >> >>They are, mostly. That is the reason why you can simulate switchers so >>blazingly fast. This does come with pitfalls and (minor) risks but it >>sure beats non-behavioral sims that take hours. > >My LT3757 boost sim runs at about 15 PPM of real time. I need seconds >of sim to model my product, so I'd get two or three runs per week. And >I'd run out of hard drive for the RAW file! > >I've ordered samples.Look thru the HELP for "alternate solver"... some types of parts require a different matrix parsing. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 26, 20132013-06-26
John Larkin wrote:> On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >> [...] >> >> >>>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>>> ONLY on their web-based simulator. >>>>>>>>> >>>>>>>> That would be a marketing decision that borders on stupid. >>>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>>> >>>>>>> (I even showed them various posts from this newsgroup complaining >>>>>>> about model quality... did no good.) >>>>>>> >>>>>> Then I assume they'll never understand why, when it comes to performance >>>>>> and cost is not a major issue, I always default to LTC and never even >>>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>>> behavioral models that work in LTSpice and AD does not. >>>>>> >>>>>> Same with TI. Who in their right mind would install and learn half a >>>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>>> is the de facto winner, oh well. >>>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>>> Cadence tool, and most amateur spin-offs. >>>>> >>>> If you run a complicated switcher non-behavioral (and I had to do that) >>>> the sims take forever. For designing SMPS that clearly is not the most >>>> efficient method. >>>> >>>> >>>>> Encrypting so a model will run only on the parent tool turns me off. >>>> Me, too. >>>> >>>> >>>>> What do you do if you want to mix LT and ADI and TI parts on your >>>>> board? You're screwed. >>>>> >>>> On high end designs I never do that, and there is no need to. You can >>>> usually get everything at LTC. Except for some hardcore RF stuff and >>>> then that gets simulated separately. >>>> >>>> If it has to be cheap then no special ICs are used anyhow most of the >>>> time. For example, my first mass-produced device with a boost converter >>>> revolves around a CD40106 as the "highest-tech" chip. There is no >>>> dedicated PWM chip because that would have added at least 10c back in >>>> the early 90's. >>>> >>>> >>>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>>> customer. Enjoy >:-} >>>>> >>>> Well, yeah, at some point you have to pick one and run with that. I have >>>> made my choice, and that choice is LTC. >>> "Most" of their stuff is good. I've had a recent situation where an >>> encrypted model works just fine on LTspice, but not on a PCB. >>> >> Same here, the LT6700 had a glitch on the chip and I was the unfortunate >> one who had to discover that the hard way. >> >> >>> The FAE was flummoxed, referred the problem to factory... 4 months >>> have passed, no solution. >>> >> In my case the LTC design engineers looked at it right away, found out >> that it was indeed a bug, fessed up, apologized, rolled up the sleeves >> and corrected things. That left a very positive impression with me. >> >> Over the years I experienced numerous similar situations with other, >> larger manufacturers. The classic solution was an attempt to cover it up. >> >> >>> I posted the problem on the LTspice list, but was basically told, >>> "LTspice, love it or leave it" :-( >>> >>> All I've been able to find out is that LTspice encrypted models are >>> behavioral internally. >>> >> They are, mostly. That is the reason why you can simulate switchers so >> blazingly fast. This does come with pitfalls and (minor) risks but it >> sure beats non-behavioral sims that take hours. > > My LT3757 boost sim runs at about 15 PPM of real time. I need seconds > of sim to model my product, so I'd get two or three runs per week. And > I'd run out of hard drive for the RAW file! >If it's not super secret send it over and I'll take a look. There's usually a way to speed things up, like by pre-charging a large cap and things like that.> I've ordered samples. >It's a good chip, I don't think you'll be disappointed. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 11:47:04 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:>On Wed, 26 Jun 2013 11:34:14 -0700, John Larkin ><jlarkin@highlandtechnology.com> wrote: > >>On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >>wrote: >> >>>Jim Thompson wrote: >>>> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>>>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jim Thompson wrote: >>>>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Jim Thompson wrote: >>> >>>[...] >>> >>> >>>>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>>>> ONLY on their web-based simulator. >>>>>>>>>> >>>>>>>>> That would be a marketing decision that borders on stupid. >>>>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>>>> >>>>>>>> (I even showed them various posts from this newsgroup complaining >>>>>>>> about model quality... did no good.) >>>>>>>> >>>>>>> Then I assume they'll never understand why, when it comes to performance >>>>>>> and cost is not a major issue, I always default to LTC and never even >>>>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>>>> behavioral models that work in LTSpice and AD does not. >>>>>>> >>>>>>> Same with TI. Who in their right mind would install and learn half a >>>>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>>>> is the de facto winner, oh well. >>>>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>>>> Cadence tool, and most amateur spin-offs. >>>>>> >>>>> If you run a complicated switcher non-behavioral (and I had to do that) >>>>> the sims take forever. For designing SMPS that clearly is not the most >>>>> efficient method. >>>>> >>>>> >>>>>> Encrypting so a model will run only on the parent tool turns me off. >>>>> >>>>> Me, too. >>>>> >>>>> >>>>>> What do you do if you want to mix LT and ADI and TI parts on your >>>>>> board? You're screwed. >>>>>> >>>>> On high end designs I never do that, and there is no need to. You can >>>>> usually get everything at LTC. Except for some hardcore RF stuff and >>>>> then that gets simulated separately. >>>>> >>>>> If it has to be cheap then no special ICs are used anyhow most of the >>>>> time. For example, my first mass-produced device with a boost converter >>>>> revolves around a CD40106 as the "highest-tech" chip. There is no >>>>> dedicated PWM chip because that would have added at least 10c back in >>>>> the early 90's. >>>>> >>>>> >>>>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>>>> customer. Enjoy >:-} >>>>>> >>>>> Well, yeah, at some point you have to pick one and run with that. I have >>>>> made my choice, and that choice is LTC. >>>> >>>> "Most" of their stuff is good. I've had a recent situation where an >>>> encrypted model works just fine on LTspice, but not on a PCB. >>>> >>> >>>Same here, the LT6700 had a glitch on the chip and I was the unfortunate >>>one who had to discover that the hard way. >>> >>> >>>> The FAE was flummoxed, referred the problem to factory... 4 months >>>> have passed, no solution. >>>> >>> >>>In my case the LTC design engineers looked at it right away, found out >>>that it was indeed a bug, fessed up, apologized, rolled up the sleeves >>>and corrected things. That left a very positive impression with me. >>> >>>Over the years I experienced numerous similar situations with other, >>>larger manufacturers. The classic solution was an attempt to cover it up. >>> >>> >>>> I posted the problem on the LTspice list, but was basically told, >>>> "LTspice, love it or leave it" :-( >>>> >>>> All I've been able to find out is that LTspice encrypted models are >>>> behavioral internally. >>>> >>> >>>They are, mostly. That is the reason why you can simulate switchers so >>>blazingly fast. This does come with pitfalls and (minor) risks but it >>>sure beats non-behavioral sims that take hours. >> >>My LT3757 boost sim runs at about 15 PPM of real time. I need seconds >>of sim to model my product, so I'd get two or three runs per week. And >>I'd run out of hard drive for the RAW file! >> >>I've ordered samples. > >Look thru the HELP for "alternate solver"... some types of parts >require a different matrix parsing. > > ...Jim ThompsonIf I improved it 20:1 it would still be too slow to give me useful feedback, and I'd still run out of hard drive. I was getting 10G RAW files from milliseconds of sim time. And I don't entirely trust the simulation; sometimes it does weird double or staggered gate drive pulses that don't make obvious sense. Besides, it's fun to solder stuff now and then. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 11:51:19 -0700, Joerg <invalid@invalid.invalid> wrote:>John Larkin wrote: >> On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>>>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jim Thompson wrote: >>>>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Jim Thompson wrote: >>> [...] >>> >>> >>>>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>>>> ONLY on their web-based simulator. >>>>>>>>>> >>>>>>>>> That would be a marketing decision that borders on stupid. >>>>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>>>> >>>>>>>> (I even showed them various posts from this newsgroup complaining >>>>>>>> about model quality... did no good.) >>>>>>>> >>>>>>> Then I assume they'll never understand why, when it comes to performance >>>>>>> and cost is not a major issue, I always default to LTC and never even >>>>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>>>> behavioral models that work in LTSpice and AD does not. >>>>>>> >>>>>>> Same with TI. Who in their right mind would install and learn half a >>>>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>>>> is the de facto winner, oh well. >>>>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>>>> Cadence tool, and most amateur spin-offs. >>>>>> >>>>> If you run a complicated switcher non-behavioral (and I had to do that) >>>>> the sims take forever. For designing SMPS that clearly is not the most >>>>> efficient method. >>>>> >>>>> >>>>>> Encrypting so a model will run only on the parent tool turns me off. >>>>> Me, too. >>>>> >>>>> >>>>>> What do you do if you want to mix LT and ADI and TI parts on your >>>>>> board? You're screwed. >>>>>> >>>>> On high end designs I never do that, and there is no need to. You can >>>>> usually get everything at LTC. Except for some hardcore RF stuff and >>>>> then that gets simulated separately. >>>>> >>>>> If it has to be cheap then no special ICs are used anyhow most of the >>>>> time. For example, my first mass-produced device with a boost converter >>>>> revolves around a CD40106 as the "highest-tech" chip. There is no >>>>> dedicated PWM chip because that would have added at least 10c back in >>>>> the early 90's. >>>>> >>>>> >>>>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>>>> customer. Enjoy >:-} >>>>>> >>>>> Well, yeah, at some point you have to pick one and run with that. I have >>>>> made my choice, and that choice is LTC. >>>> "Most" of their stuff is good. I've had a recent situation where an >>>> encrypted model works just fine on LTspice, but not on a PCB. >>>> >>> Same here, the LT6700 had a glitch on the chip and I was the unfortunate >>> one who had to discover that the hard way. >>> >>> >>>> The FAE was flummoxed, referred the problem to factory... 4 months >>>> have passed, no solution. >>>> >>> In my case the LTC design engineers looked at it right away, found out >>> that it was indeed a bug, fessed up, apologized, rolled up the sleeves >>> and corrected things. That left a very positive impression with me. >>> >>> Over the years I experienced numerous similar situations with other, >>> larger manufacturers. The classic solution was an attempt to cover it up. >>> >>> >>>> I posted the problem on the LTspice list, but was basically told, >>>> "LTspice, love it or leave it" :-( >>>> >>>> All I've been able to find out is that LTspice encrypted models are >>>> behavioral internally. >>>> >>> They are, mostly. That is the reason why you can simulate switchers so >>> blazingly fast. This does come with pitfalls and (minor) risks but it >>> sure beats non-behavioral sims that take hours. >> >> My LT3757 boost sim runs at about 15 PPM of real time. I need seconds >> of sim to model my product, so I'd get two or three runs per week. And >> I'd run out of hard drive for the RAW file! >> > >If it's not super secret send it over and I'll take a look. There's >usually a way to speed things up, like by pre-charging a large cap and >things like that.No secret, here it is. But C1 needs to be 4000 uF in real life, and I want to see how it ramps up and stabilizes, and how it recovers after a big load pulse. I'm making 10G RAW files in milliseconds of sim time, and I need seconds. But if you know of any tweaks that would speed it up, I'd appreciate that. 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1424 640 R0 WINDOW 3 -90 -82 Left 2 SYMATTR Value V=100 * I(R6) * V(VP) / ( I(R8) * 9 ) SYMATTR InstName B1 SYMBOL res 1408 336 R0 WINDOW 0 -72 62 Left 2 WINDOW 3 -73 94 Left 2 SYMATTR InstName R10 SYMATTR Value 10m TEXT 720 752 Left 2 !.tran 0 30m 0 10n uic TEXT 704 656 Left 2 ;D140 BOOST SUPPLY DA TEXT 744 696 Left 2 ;JL June 24 2013 TEXT 712 248 Left 2 !K L1 L2 0.99 -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●June 26, 20132013-06-26
John Larkin wrote:> On Wed, 26 Jun 2013 11:47:04 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >> On Wed, 26 Jun 2013 11:34:14 -0700, John Larkin >> <jlarkin@highlandtechnology.com> wrote:[...]>>> My LT3757 boost sim runs at about 15 PPM of real time. I need seconds >>> of sim to model my product, so I'd get two or three runs per week. And >>> I'd run out of hard drive for the RAW file! >>> >>> I've ordered samples. >> Look thru the HELP for "alternate solver"... some types of parts >> require a different matrix parsing. >> >> ...Jim Thompson > > If I improved it 20:1 it would still be too slow to give me useful > feedback, and I'd still run out of hard drive. I was getting 10G RAW > files from milliseconds of sim time. > > And I don't entirely trust the simulation; sometimes it does weird > double or staggered gate drive pulses that don't make obvious sense. > > Besides, it's fun to solder stuff now and then. >When a chip like the LT3757 isn't maxed out in frequency and gate capacitance load I usually provide an 0.080" via underneath. Mostly without thermal relief to the plane. That way I can reach in with a Weller ETS tip to get it off the board. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●June 26, 20132013-06-26
On Wed, 26 Jun 2013 11:57:42 -0700, John Larkin <jlarkin@highlandtechnology.com> wrote:>On Wed, 26 Jun 2013 11:47:04 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Wed, 26 Jun 2013 11:34:14 -0700, John Larkin >><jlarkin@highlandtechnology.com> wrote: >> >>>On Wed, 26 Jun 2013 10:54:54 -0700, Joerg <invalid@invalid.invalid> >>>wrote: >>> >>>>Jim Thompson wrote: >>>>> On Wed, 26 Jun 2013 10:04:19 -0700, Joerg <invalid@invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Wed, 26 Jun 2013 09:26:58 -0700, Joerg <invalid@invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >>>>>>>>> On Wed, 26 Jun 2013 09:08:52 -0700, Joerg <invalid@invalid.invalid> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Jim Thompson wrote: >>>> >>>>[...] >>>> >>>> >>>>>>>>>>> And Analog Devices modeling efforts are now managed by a MARKETING VP, >>>>>>>>>>> and they are ultimately heading to requiring simulation of their parts >>>>>>>>>>> ONLY on their web-based simulator. >>>>>>>>>>> >>>>>>>>>> That would be a marketing decision that borders on stupid. >>>>>>>>> I was there (San Jose) last August trying to convince them of the best >>>>>>>>> way to do modeling... let me see the real netlist and then I'd match >>>>>>>>> it behaviorally. The MARKETING VP nixed the idea. >>>>>>>>> >>>>>>>>> (I even showed them various posts from this newsgroup complaining >>>>>>>>> about model quality... did no good.) >>>>>>>>> >>>>>>>> Then I assume they'll never understand why, when it comes to performance >>>>>>>> and cost is not a major issue, I always default to LTC and never even >>>>>>>> look at AD unless I can't find a chip at LTC. This is because LTC has >>>>>>>> behavioral models that work in LTSpice and AD does not. >>>>>>>> >>>>>>>> Same with TI. Who in their right mind would install and learn half a >>>>>>>> dozen competing "free" simulators? If they can't understand that LTSpice >>>>>>>> is the de facto winner, oh well. >>>>>>> PSpice will run ANY non-encrypted model, as will LTspice, HSpice, any >>>>>>> Cadence tool, and most amateur spin-offs. >>>>>>> >>>>>> If you run a complicated switcher non-behavioral (and I had to do that) >>>>>> the sims take forever. For designing SMPS that clearly is not the most >>>>>> efficient method. >>>>>> >>>>>> >>>>>>> Encrypting so a model will run only on the parent tool turns me off. >>>>>> >>>>>> Me, too. >>>>>> >>>>>> >>>>>>> What do you do if you want to mix LT and ADI and TI parts on your >>>>>>> board? You're screwed. >>>>>>> >>>>>> On high end designs I never do that, and there is no need to. You can >>>>>> usually get everything at LTC. Except for some hardcore RF stuff and >>>>>> then that gets simulated separately. >>>>>> >>>>>> If it has to be cheap then no special ICs are used anyhow most of the >>>>>> time. For example, my first mass-produced device with a boost converter >>>>>> revolves around a CD40106 as the "highest-tech" chip. There is no >>>>>> dedicated PWM chip because that would have added at least 10c back in >>>>>> the early 90's. >>>>>> >>>>>> >>>>>>> Joerg, sounds like LT is happy as a clam with you. You're a locked-in >>>>>>> customer. Enjoy >:-} >>>>>>> >>>>>> Well, yeah, at some point you have to pick one and run with that. I have >>>>>> made my choice, and that choice is LTC. >>>>> >>>>> "Most" of their stuff is good. I've had a recent situation where an >>>>> encrypted model works just fine on LTspice, but not on a PCB. >>>>> >>>> >>>>Same here, the LT6700 had a glitch on the chip and I was the unfortunate >>>>one who had to discover that the hard way. >>>> >>>> >>>>> The FAE was flummoxed, referred the problem to factory... 4 months >>>>> have passed, no solution. >>>>> >>>> >>>>In my case the LTC design engineers looked at it right away, found out >>>>that it was indeed a bug, fessed up, apologized, rolled up the sleeves >>>>and corrected things. That left a very positive impression with me. >>>> >>>>Over the years I experienced numerous similar situations with other, >>>>larger manufacturers. The classic solution was an attempt to cover it up. >>>> >>>> >>>>> I posted the problem on the LTspice list, but was basically told, >>>>> "LTspice, love it or leave it" :-( >>>>> >>>>> All I've been able to find out is that LTspice encrypted models are >>>>> behavioral internally. >>>>> >>>> >>>>They are, mostly. That is the reason why you can simulate switchers so >>>>blazingly fast. This does come with pitfalls and (minor) risks but it >>>>sure beats non-behavioral sims that take hours. >>> >>>My LT3757 boost sim runs at about 15 PPM of real time. I need seconds >>>of sim to model my product, so I'd get two or three runs per week. And >>>I'd run out of hard drive for the RAW file! >>> >>>I've ordered samples. >> >>Look thru the HELP for "alternate solver"... some types of parts >>require a different matrix parsing. >> >> ...Jim Thompson > >If I improved it 20:1 it would still be too slow to give me useful >feedback, and I'd still run out of hard drive. I was getting 10G RAW >files from milliseconds of sim time. > >And I don't entirely trust the simulation; sometimes it does weird >double or staggered gate drive pulses that don't make obvious sense. > >Besides, it's fun to solder stuff now and then.Some of those LT parts are known by those of us "versed in the art" to have _real_ bugs. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
