Forums

LTspice heads up

Started by Jim Thompson October 28, 2015
LTspice heads up...

Latest LTspice sync release over-wrote many text-based subcircuits
with encrypted versions.

So back up all the text-based ones before they disappear.
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             |
| 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.
On 10/28/2015 2:33 PM, Jim Thompson wrote:
> LTspice heads up... > > Latest LTspice sync release over-wrote many text-based subcircuits > with encrypted versions. > > So back up all the text-based ones before they disappear.
Hasn't that always been the case? I recall that you should always back up LTspice device models. -- Rick
On Wed, 28 Oct 2015 15:22:12 -0400, rickman <gnuarm@gmail.com> wrote:

>On 10/28/2015 2:33 PM, Jim Thompson wrote: >> LTspice heads up... >> >> Latest LTspice sync release over-wrote many text-based subcircuits >> with encrypted versions. >> >> So back up all the text-based ones before they disappear. > >Hasn't that always been the case? I recall that you should always back >up LTspice device models.
I save all of my older LTspice download EXEs so that I can always go back. Sometimes there is a bug that you can't deal with so that's another good reason to keep old installations around.... Then can check the operation of a newer vs. older LTspice as well for speed and/or accuracy or whatever. boB K7IQ
On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>LTspice heads up... > >Latest LTspice sync release over-wrote many text-based subcircuits >with encrypted versions. > >So back up all the text-based ones before they disappear. > > ...Jim Thompson
Does Ver4 Pspice run encrypted subcircuits? Will LTspice begin to handle encrypted models that currently demand Pspice Rev9 or higher? RL
On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote:

>On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>LTspice heads up... >> >>Latest LTspice sync release over-wrote many text-based subcircuits >>with encrypted versions. >> >>So back up all the text-based ones before they disappear. >> >> ...Jim Thompson > >Does Ver4 Pspice run encrypted subcircuits? > >Will LTspice begin to handle encrypted models that currently demand >Pspice Rev9 or higher? > >RL
The problem is that every simulator has its own version of encryption... LTspice encryptions won't run on PSpice and vice versa. My defense (offense ?:-) is to write models that are simulator-independent. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | 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.
On Thu, 29 Oct 2015 18:25:14 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote: > >>On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>LTspice heads up... >>> >>>Latest LTspice sync release over-wrote many text-based subcircuits >>>with encrypted versions. >>> >>>So back up all the text-based ones before they disappear. >>> >>> ...Jim Thompson >> >>Does Ver4 Pspice run encrypted subcircuits? >> >>Will LTspice begin to handle encrypted models that currently demand >>Pspice Rev9 or higher? >> >>RL > >The problem is that every simulator has its own version of >encryption... LTspice encryptions won't run on PSpice and vice versa. > >My defense (offense ?:-) is to write models that are >simulator-independent. > > ...Jim Thompson
I should have added... the in-house Spice-modelers are usually PhD's... aka village idiots, when it comes to modeling... just look at the trash that comes out of Microchip. So I will amuse myself by writing models from their datasheets that outperform their models (and they have the device-level netlists). Bunch-a-dummies. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | 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.
On Thu, 29 Oct 2015 18:25:14 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote: > >>On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>LTspice heads up... >>> >>>Latest LTspice sync release over-wrote many text-based subcircuits >>>with encrypted versions. >>> >>>So back up all the text-based ones before they disappear. >>> >>> ...Jim Thompson >> >>Does Ver4 Pspice run encrypted subcircuits? >> >>Will LTspice begin to handle encrypted models that currently demand >>Pspice Rev9 or higher? >> >>RL > >The problem is that every simulator has its own version of >encryption... LTspice encryptions won't run on PSpice and vice versa. >
Can't see how that would make much sense. Linear Tech sells ICs, not LTpice simulator software. I'd assumed that previous unencrypted LTspice models worked on Pspice... RL
On 30/10/2015 12:29, Jim Thompson wrote:
> On Thu, 29 Oct 2015 18:25:14 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >> On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote: >> >>> On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>> LTspice heads up... >>>> >>>> Latest LTspice sync release over-wrote many text-based subcircuits >>>> with encrypted versions. >>>> >>>> So back up all the text-based ones before they disappear. >>>> >>>> ...Jim Thompson >>> >>> Does Ver4 Pspice run encrypted subcircuits? >>> >>> Will LTspice begin to handle encrypted models that currently demand >>> Pspice Rev9 or higher? >>> >>> RL >> >> The problem is that every simulator has its own version of >> encryption... LTspice encryptions won't run on PSpice and vice versa. >> >> My defense (offense ?:-) is to write models that are >> simulator-independent. >> >> ...Jim Thompson > > I should have added... the in-house Spice-modelers are usually > PhD's... aka village idiots, when it comes to modeling... just look at > the trash that comes out of Microchip.
It wouldn't surprise me if the models they give to customers are written by people in sales/marketing who have no access to the device level netlists, just like the datasheets are often written by people who had nothing to do with the circuit design. I was sometimes surprised and quite amused by the block diagrams that appeared in the datasheets of chips that I designed circuitry for. The spice modellers who work on the models USED in-house were extremely competent, but those models were totally separate from anything a customer would ever get to see. After all if the models used in design verification were wrong, that would result in new mask sets and massive costs and delays, whereas spice models for customers are just a tick-box exercise.
> So I will amuse myself by writing models from their datasheets that > outperform their models (and they have the device-level netlists).
It is sad that chip companies have detailed and accurate models of their parts for design validation, but then assume that customers are happy with any old behavioural model that misses out most of the subtleties of the behaviour. Any other chip company can easily get complete reverse-engineered netlists of competitor parts, so the secrecy is pointless. Chris
legg <legg@nospam.magma.ca> writes:

> On Thu, 29 Oct 2015 18:25:14 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote: >> >>>On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>LTspice heads up... >>>> >>>>Latest LTspice sync release over-wrote many text-based subcircuits >>>>with encrypted versions. >>>> >>>>So back up all the text-based ones before they disappear. >>>> >>>> ...Jim Thompson >>> >>>Does Ver4 Pspice run encrypted subcircuits? >>> >>>Will LTspice begin to handle encrypted models that currently demand >>>Pspice Rev9 or higher? >>> >>>RL >> >>The problem is that every simulator has its own version of >>encryption... LTspice encryptions won't run on PSpice and vice versa. >> > Can't see how that would make much sense. Linear Tech sells ICs, not > LTpice simulator software.
They are paranoid about other manufacturers learning the innards of their parts via the spice models published? I think there is a clause in the license about LTSpice not being legal to use by their competitors or for chip design.
> I'd assumed that previous unencrypted LTspice models worked on > Pspice... > > RL
-- John Devereux
On Thu, 29 Oct 2015 22:01:17 -0400, legg <legg@nospam.magma.ca> wrote:

>On Thu, 29 Oct 2015 18:25:14 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Thu, 29 Oct 2015 20:20:57 -0400, legg <legg@nospam.magma.ca> wrote: >> >>>On Wed, 28 Oct 2015 11:33:50 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>LTspice heads up... >>>> >>>>Latest LTspice sync release over-wrote many text-based subcircuits >>>>with encrypted versions. >>>> >>>>So back up all the text-based ones before they disappear. >>>> >>>> ...Jim Thompson >>> >>>Does Ver4 Pspice run encrypted subcircuits? >>> >>>Will LTspice begin to handle encrypted models that currently demand >>>Pspice Rev9 or higher? >>> >>>RL >> >>The problem is that every simulator has its own version of >>encryption... LTspice encryptions won't run on PSpice and vice versa. >> >Can't see how that would make much sense. Linear Tech sells ICs, not >LTpice simulator software.
I think Mike is trying to hide the sleights-of-hand he uses to speed up simulations. Also ponder the following statement from _SCAD4_Manual_, particularly consider why there are two netlist "parsers": "Also interesting is which solver is used. LTspice contains two complete versions of SPICE. One is called the normal solver and the other is called the alternate solver. The alternate solver uses a different sparse matrix package with reduced roundoff error. Typically the alternate solver will simulate at half the speed of the normal solver but with one thousand times more internal accuracy. This can be a useful diagnostic to have available. There is no .option to specify which solver is used, the choice must be made before the netlist is parsed because the two solvers use different parsers." The normal solver hangs and churns forever on many Berkeley-Spice-compliant models. Wonder why ?>:-} Since there's no .OUT file generated by LTspice, one can't compare and see what models are used for "normal" versus "alternate". My suspicion is that "normal" substitutes over-simplified behavioral models to enhance the speed (like idealized diodes, etc) and barfs when its linearizations methods encounter an unusual model. I discovered this when I ran a device with an S-shaped transfer curve thru LTspice. LTspice "normal" solver completely linearized it, then hung half-way thru the simulation. It matches real-world and PSpice if you select the "alternate" solver. So I've recommended to my clients that use LTspice to always set "alternate" solver... slower by about a factor of two, but accurate.
> >I'd assumed that previous unencrypted LTspice models worked on >Pspice... > >RL
Yes. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | 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.