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LTSpice: Slow on noise sims with foreign opamps

Started by Joerg January 4, 2013
On Fri, 04 Jan 2013 18:09:42 -0800, Joerg <invalid@invalid.invalid>
wrote:

>Jim Thompson wrote: >> On Fri, 04 Jan 2013 17:52:41 -0800, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Rich Webb wrote: >>>> On Fri, 04 Jan 2013 14:03:34 -0800, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>>>>> On Fri, 04 Jan 2013 12:21:05 -0800, Joerg <invalid@invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jim Thompson wrote: >>>>>>>> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Folks, >>>>>>>>> >>>>>>>>> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >>>>>>>>> that I'll ask here instead of the LTSpice group: >>>>>>>> What? You refused to identify yourself with a Username and Password >>>>>>>> ?>:-} >>>>>>>> >>>>>>> I did ID myself. But now they slapped on a stupid "captcha". Which >>>>>>> promptly resulted in "Can't identify the machine bla-bla-bla, followed >>>>>>> by a challenge question to which they cannot have the answer. >>>>>> Do we live in the same universe? I've never experienced that. >>>>>> >>>>> Tried numerous times, always the captcha. Those things are nasty but >>>>> after four tries it let me past the virtual bouncer. Wot a pain. >>>> No captcha here, either. I'm not a "member" of the LTSpice Yahoo! >>>> (can't forget the '!') group but am of a couple of others in the >>>> tech.groups.yahoo.com tree. Maybe something with your browser (is >>>> javascript on? needed?) or cookie settings? >>>> >>>> If not, it may be that somebody (or some algorithm) has decided that >>>> your login is being used by a 'bot, since 'bot blocking is the usual >>>> reason for putting a captha in-line with the login. >>> >>> Maybe because I leave myself logged in until it throws me off. Usually >>> lasts a few weeks. I really don't like log-in hassles. Why can't they >>> just set a cookie and be done with it? >> >> They can. You probably have it blocked. Mine works.... Firefox >> v17.0.1 >> > >I always turn cookie on when I look onto the, it's sitchable.
You need to be careful while "sitching" ;-) ...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 | I love to cook with wine. Sometimes I even put it in the food.
On 2013-01-04, Joerg <invalid@invalid.invalid> wrote:
> Folks, > > Yahoo has made the sign-in procedure so onerous (can't get in anymore) > that I'll ask here instead of the LTSpice group: > > I want to do some noise simulations, for example with a TI opamp in > there. Loading the complete model it spends forever in the stepping > phase, then pseudo-damped analysis and whatnot. > > Is there any way this can be sped up? All I need to see is ballpark > where the 1/f knees will be with various circuit constellations, input > current noise, input voltage noise, stuff like that.
If you want to play with TI psrts perhaps try the free TI spice program "TINA" -- &#9858;&#9859; 100% natural --- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Usually if spice is choking, there is something wrong with the circuit. 
Now you can't float single nodes in spice, but you can have nets that 
should be tied to something that might be floating.

I would look carefully at the connectivity of the subcircuit.
Jim Thompson wrote:
> On Fri, 04 Jan 2013 17:50:46 -0800, Joerg <invalid@invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Fri, 04 Jan 2013 17:16:15 -0800, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Fri, 04 Jan 2013 16:36:12 -0800, Joerg <invalid@invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Fri, 04 Jan 2013 14:56:52 -0800, Joerg <invalid@invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >>>>>>>>> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Folks, >>>>>>>>>> >>>>>>>>>> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >>>>>>>>>> that I'll ask here instead of the LTSpice group: >>>>>>>>>> >>>>>>>>>> I want to do some noise simulations, for example with a TI opamp in >>>>>>>>>> there. Loading the complete model it spends forever in the stepping >>>>>>>>>> phase, then pseudo-damped analysis and whatnot. >>>>>>>>>> >>>>>>>>>> Is there any way this can be sped up? All I need to see is ballpark >>>>>>>>>> where the 1/f knees will be with various circuit constellations, input >>>>>>>>>> current noise, input voltage noise, stuff like that. >>>>>>>>> Bwahahahahahaha! The OPA4140 Spice model provided by TI is what gives >>>>>>>>> model-makers a bad name... the sort of model you get when you take a >>>>>>>>> PhD with no hands-on-lab experience and sit them down in front of a >>>>>>>>> simulator. >>>>>>>>> >>>>>>>>> I don't think I've ever seen such a badly constructed model before. No >>>>>>>>> wonder it takes forever to converge. >>>>>>>>> >>>>>>>> Kind of my hunch, but I hadn't thought it was this bad :-( >>>>>>>> >>>>>>>> Burr-Brown used to be a pretty good bunch of engineers, real hands-on guys. >>>>>>>> >>>>>>>> Looking at the bright side it did manage to heat my office by one degree >>>>>>>> Fahrenheit over lunch. >>>>>>> Hmmmmmm? Maybe cockpit error? In PSpice, Q-point found as fast as >>>>>>> you can blink: >>>>>>> >>>>>>> **** 01/04/13 17:12:37 ******* PSpice 15.7.0 (July 2006) ****** ID# >>>>>>> xxxxxxxx * >>>>>>> >>>>>>> * C:\Projects\Expments\OpAmps\OPA4140.sch >>>>>>> >>>>>>> >>>>>>> **** JOB STATISTICS SUMMARY >>>>>>> >>>>>>> >>>>>>> ****************************************************************************** >>>>>>> >>>>>>> >>>>>>> >>>>>>> Total job time (using Solver 1) = .27 <<<<<<<<<<< >>>>>>> >>>>>>> See... >>>>>>> >>>>>>> http://www.analog-innovations.com/SED/OPA4140_Q-Point.pdf >>>>>>> >>>>>>> What set-up do you want? >>>>>>> >>>>>>> Noise info for what frequency range? >>>>>>> >>>>>> I'll have to include it in a measurement set-up and play around with >>>>>> component values to find a good compromise. Possibly they have included >>>>>> something that LTSpice does not like. I doubt cockpit error because >>>>>> various other opamps run blink-eye speed here as well. Plus I did not >>>>>> have a sip of the Fin du Monde ale yet, that's for later tonight. >>>>>> >>>>> >From a noise point of view I think we can do a tad better than the 4140 >>>>>> anyhow. It's mostly up to a coupole hundred keelohoitzes in this case, >>>>>> no RF stuff. >>>>>> >>>>>> Thanks for testing it. In case you want to try: When you hang a 10k in >>>>>> the FB and feed a current into IN-, then runs .NOISE, does it run on >>>>>> your sim? If yes then it's highly likely that the model doesn't fit LTSpice. >>>>> I think I know the problem... >>>>> >>>>> I did this... >>>>> >>>>> .SUBCKT OPA4140 +IN -IN Vout V+ V- ; -IN +IN V- V+ Vout (Rearranged >>>>> Order to Match PSpice Symbol) >>>>> >>>>> You need to make sure the "pin" order matches the LTspice OpAmp >>>>> symbol... otherwise you will experience pain and agony. >>>>> >>>>> (The TI pin order is just a wee bit unusual. I do this rearrangement >>>>> exercise almost daily, so it's second nature to me.) >>>>> >>>> Then I get this: >>>> >>>> Circuit: * E:\Simulations\PGL\PosSense_AC_1.asc >>>> >>>> Expanding empty subcircuit: opa4140 >>>> WARNING: Less than two connections to node V+. This node is used by V1. >>>> WARNING: Less than two connections to node V-. This node is used by V2. >>>> Direct Newton iteration for .op point succeeded. >>>> >>>> Date: Fri Jan 04 17:14:43 2013 >>>> Total elapsed time: 0.047 seconds. >>>> >>>> tnom = 27 >>>> temp = 27 >>>> method = trap >>>> totiter = 6 >>>> traniter = 0 >>>> tranpoints = 0 >>>> accept = 0 >>>> rejected = 0 >>>> matrix size = 17 >>>> fillins = 0 >>>> solver = Normal >>>> Matrix Compiler1: 32 opcodes >>>> Matrix Compiler2: 967 bytes object code size >>> That is so-o-o-o-o useful. WTF does that mean? Does it work, or not? >>> >> Nope. This was the error message LTSpice let off. > > Huh? What does... > > "Direct Newton iteration for .op point succeeded." <<<<<< > > ... mean? >
Nothing in this case because LTSpice stopped. Plus it normally never opens such message windows unless it is unhappy with something. The usual waveform window never opened and that's a clear sign that it ain't happy. -- Regards, Joerg http://www.analogconsultants.com/
Jasen Betts wrote:
> On 2013-01-04, Joerg <invalid@invalid.invalid> wrote: >> Folks, >> >> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >> that I'll ask here instead of the LTSpice group: >> >> I want to do some noise simulations, for example with a TI opamp in >> there. Loading the complete model it spends forever in the stepping >> phase, then pseudo-damped analysis and whatnot. >> >> Is there any way this can be sped up? All I need to see is ballpark >> where the 1/f knees will be with various circuit constellations, input >> current noise, input voltage noise, stuff like that. > > If you want to play with TI psrts perhaps try the free TI spice program > "TINA" >
Well, I don't want to learn a new CAD everytime a vendor thinks they absolutely have to boil their own proprietary broth. The stuff I do with it often gets to be complicated and that would take a long learning curve every time. -- Regards, Joerg http://www.analogconsultants.com/
On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid>
wrote:

>Folks, > >Yahoo has made the sign-in procedure so onerous (can't get in anymore) >that I'll ask here instead of the LTSpice group: > >I want to do some noise simulations, for example with a TI opamp in >there. Loading the complete model it spends forever in the stepping >phase, then pseudo-damped analysis and whatnot. > >Is there any way this can be sped up? All I need to see is ballpark >where the 1/f knees will be with various circuit constellations, input >current noise, input voltage noise, stuff like that.
See... http://www.analog-innovations.com/SED/Greenshot_2013-01-05_09-42-15_Joerg_Noise.png ...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 | I love to cook with wine. Sometimes I even put it in the food.
On Sat, 05 Jan 2013 08:42:30 -0800, Joerg <invalid@invalid.invalid>
wrote:

>Jim Thompson wrote: >> On Fri, 04 Jan 2013 17:50:46 -0800, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Fri, 04 Jan 2013 17:16:15 -0800, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> Jim Thompson wrote: >>>>>> On Fri, 04 Jan 2013 16:36:12 -0800, Joerg <invalid@invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Jim Thompson wrote: >>>>>>>> On Fri, 04 Jan 2013 14:56:52 -0800, Joerg <invalid@invalid.invalid> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Jim Thompson wrote: >>>>>>>>>> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> Folks, >>>>>>>>>>> >>>>>>>>>>> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >>>>>>>>>>> that I'll ask here instead of the LTSpice group: >>>>>>>>>>> >>>>>>>>>>> I want to do some noise simulations, for example with a TI opamp in >>>>>>>>>>> there. Loading the complete model it spends forever in the stepping >>>>>>>>>>> phase, then pseudo-damped analysis and whatnot. >>>>>>>>>>> >>>>>>>>>>> Is there any way this can be sped up? All I need to see is ballpark >>>>>>>>>>> where the 1/f knees will be with various circuit constellations, input >>>>>>>>>>> current noise, input voltage noise, stuff like that. >>>>>>>>>> Bwahahahahahaha! The OPA4140 Spice model provided by TI is what gives >>>>>>>>>> model-makers a bad name... the sort of model you get when you take a >>>>>>>>>> PhD with no hands-on-lab experience and sit them down in front of a >>>>>>>>>> simulator. >>>>>>>>>> >>>>>>>>>> I don't think I've ever seen such a badly constructed model before. No >>>>>>>>>> wonder it takes forever to converge. >>>>>>>>>> >>>>>>>>> Kind of my hunch, but I hadn't thought it was this bad :-( >>>>>>>>> >>>>>>>>> Burr-Brown used to be a pretty good bunch of engineers, real hands-on guys. >>>>>>>>> >>>>>>>>> Looking at the bright side it did manage to heat my office by one degree >>>>>>>>> Fahrenheit over lunch. >>>>>>>> Hmmmmmm? Maybe cockpit error? In PSpice, Q-point found as fast as >>>>>>>> you can blink: >>>>>>>> >>>>>>>> **** 01/04/13 17:12:37 ******* PSpice 15.7.0 (July 2006) ****** ID# >>>>>>>> xxxxxxxx * >>>>>>>> >>>>>>>> * C:\Projects\Expments\OpAmps\OPA4140.sch >>>>>>>> >>>>>>>> >>>>>>>> **** JOB STATISTICS SUMMARY >>>>>>>> >>>>>>>> >>>>>>>> ****************************************************************************** >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Total job time (using Solver 1) = .27 <<<<<<<<<<< >>>>>>>> >>>>>>>> See... >>>>>>>> >>>>>>>> http://www.analog-innovations.com/SED/OPA4140_Q-Point.pdf >>>>>>>> >>>>>>>> What set-up do you want? >>>>>>>> >>>>>>>> Noise info for what frequency range? >>>>>>>> >>>>>>> I'll have to include it in a measurement set-up and play around with >>>>>>> component values to find a good compromise. Possibly they have included >>>>>>> something that LTSpice does not like. I doubt cockpit error because >>>>>>> various other opamps run blink-eye speed here as well. Plus I did not >>>>>>> have a sip of the Fin du Monde ale yet, that's for later tonight. >>>>>>> >>>>>> >From a noise point of view I think we can do a tad better than the 4140 >>>>>>> anyhow. It's mostly up to a coupole hundred keelohoitzes in this case, >>>>>>> no RF stuff. >>>>>>> >>>>>>> Thanks for testing it. In case you want to try: When you hang a 10k in >>>>>>> the FB and feed a current into IN-, then runs .NOISE, does it run on >>>>>>> your sim? If yes then it's highly likely that the model doesn't fit LTSpice. >>>>>> I think I know the problem... >>>>>> >>>>>> I did this... >>>>>> >>>>>> .SUBCKT OPA4140 +IN -IN Vout V+ V- ; -IN +IN V- V+ Vout (Rearranged >>>>>> Order to Match PSpice Symbol) >>>>>> >>>>>> You need to make sure the "pin" order matches the LTspice OpAmp >>>>>> symbol... otherwise you will experience pain and agony. >>>>>> >>>>>> (The TI pin order is just a wee bit unusual. I do this rearrangement >>>>>> exercise almost daily, so it's second nature to me.) >>>>>> >>>>> Then I get this: >>>>> >>>>> Circuit: * E:\Simulations\PGL\PosSense_AC_1.asc >>>>> >>>>> Expanding empty subcircuit: opa4140 >>>>> WARNING: Less than two connections to node V+. This node is used by V1. >>>>> WARNING: Less than two connections to node V-. This node is used by V2. >>>>> Direct Newton iteration for .op point succeeded. >>>>> >>>>> Date: Fri Jan 04 17:14:43 2013 >>>>> Total elapsed time: 0.047 seconds. >>>>> >>>>> tnom = 27 >>>>> temp = 27 >>>>> method = trap >>>>> totiter = 6 >>>>> traniter = 0 >>>>> tranpoints = 0 >>>>> accept = 0 >>>>> rejected = 0 >>>>> matrix size = 17 >>>>> fillins = 0 >>>>> solver = Normal >>>>> Matrix Compiler1: 32 opcodes >>>>> Matrix Compiler2: 967 bytes object code size >>>> That is so-o-o-o-o useful. WTF does that mean? Does it work, or not? >>>> >>> Nope. This was the error message LTSpice let off. >> >> Huh? What does... >> >> "Direct Newton iteration for .op point succeeded." <<<<<< >> >> ... mean? >> > >Nothing in this case because LTSpice stopped. Plus it normally never >opens such message windows unless it is unhappy with something. The >usual waveform window never opened and that's a clear sign that it ain't >happy.
Nope. It means that it DID find the OPerating point. You probably don't have the .AC set up properly. I've just posted another pass. ...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 | I love to cook with wine. Sometimes I even put it in the food.
Jim Thompson wrote:
> On Sat, 05 Jan 2013 08:42:30 -0800, Joerg <invalid@invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Fri, 04 Jan 2013 17:50:46 -0800, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Fri, 04 Jan 2013 17:16:15 -0800, Joerg <invalid@invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Fri, 04 Jan 2013 16:36:12 -0800, Joerg <invalid@invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >>>>>>>>> On Fri, 04 Jan 2013 14:56:52 -0800, Joerg <invalid@invalid.invalid> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Jim Thompson wrote: >>>>>>>>>>> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> Folks, >>>>>>>>>>>> >>>>>>>>>>>> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >>>>>>>>>>>> that I'll ask here instead of the LTSpice group: >>>>>>>>>>>> >>>>>>>>>>>> I want to do some noise simulations, for example with a TI opamp in >>>>>>>>>>>> there. Loading the complete model it spends forever in the stepping >>>>>>>>>>>> phase, then pseudo-damped analysis and whatnot. >>>>>>>>>>>> >>>>>>>>>>>> Is there any way this can be sped up? All I need to see is ballpark >>>>>>>>>>>> where the 1/f knees will be with various circuit constellations, input >>>>>>>>>>>> current noise, input voltage noise, stuff like that. >>>>>>>>>>> Bwahahahahahaha! The OPA4140 Spice model provided by TI is what gives >>>>>>>>>>> model-makers a bad name... the sort of model you get when you take a >>>>>>>>>>> PhD with no hands-on-lab experience and sit them down in front of a >>>>>>>>>>> simulator. >>>>>>>>>>> >>>>>>>>>>> I don't think I've ever seen such a badly constructed model before. No >>>>>>>>>>> wonder it takes forever to converge. >>>>>>>>>>> >>>>>>>>>> Kind of my hunch, but I hadn't thought it was this bad :-( >>>>>>>>>> >>>>>>>>>> Burr-Brown used to be a pretty good bunch of engineers, real hands-on guys. >>>>>>>>>> >>>>>>>>>> Looking at the bright side it did manage to heat my office by one degree >>>>>>>>>> Fahrenheit over lunch. >>>>>>>>> Hmmmmmm? Maybe cockpit error? In PSpice, Q-point found as fast as >>>>>>>>> you can blink: >>>>>>>>> >>>>>>>>> **** 01/04/13 17:12:37 ******* PSpice 15.7.0 (July 2006) ****** ID# >>>>>>>>> xxxxxxxx * >>>>>>>>> >>>>>>>>> * C:\Projects\Expments\OpAmps\OPA4140.sch >>>>>>>>> >>>>>>>>> >>>>>>>>> **** JOB STATISTICS SUMMARY >>>>>>>>> >>>>>>>>> >>>>>>>>> ****************************************************************************** >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Total job time (using Solver 1) = .27 <<<<<<<<<<< >>>>>>>>> >>>>>>>>> See... >>>>>>>>> >>>>>>>>> http://www.analog-innovations.com/SED/OPA4140_Q-Point.pdf >>>>>>>>> >>>>>>>>> What set-up do you want? >>>>>>>>> >>>>>>>>> Noise info for what frequency range? >>>>>>>>> >>>>>>>> I'll have to include it in a measurement set-up and play around with >>>>>>>> component values to find a good compromise. Possibly they have included >>>>>>>> something that LTSpice does not like. I doubt cockpit error because >>>>>>>> various other opamps run blink-eye speed here as well. Plus I did not >>>>>>>> have a sip of the Fin du Monde ale yet, that's for later tonight. >>>>>>>> >>>>>>> >From a noise point of view I think we can do a tad better than the 4140 >>>>>>>> anyhow. It's mostly up to a coupole hundred keelohoitzes in this case, >>>>>>>> no RF stuff. >>>>>>>> >>>>>>>> Thanks for testing it. In case you want to try: When you hang a 10k in >>>>>>>> the FB and feed a current into IN-, then runs .NOISE, does it run on >>>>>>>> your sim? If yes then it's highly likely that the model doesn't fit LTSpice. >>>>>>> I think I know the problem... >>>>>>> >>>>>>> I did this... >>>>>>> >>>>>>> .SUBCKT OPA4140 +IN -IN Vout V+ V- ; -IN +IN V- V+ Vout (Rearranged >>>>>>> Order to Match PSpice Symbol) >>>>>>> >>>>>>> You need to make sure the "pin" order matches the LTspice OpAmp >>>>>>> symbol... otherwise you will experience pain and agony. >>>>>>> >>>>>>> (The TI pin order is just a wee bit unusual. I do this rearrangement >>>>>>> exercise almost daily, so it's second nature to me.) >>>>>>> >>>>>> Then I get this: >>>>>> >>>>>> Circuit: * E:\Simulations\PGL\PosSense_AC_1.asc >>>>>> >>>>>> Expanding empty subcircuit: opa4140 >>>>>> WARNING: Less than two connections to node V+. This node is used by V1. >>>>>> WARNING: Less than two connections to node V-. This node is used by V2. >>>>>> Direct Newton iteration for .op point succeeded. >>>>>> >>>>>> Date: Fri Jan 04 17:14:43 2013 >>>>>> Total elapsed time: 0.047 seconds. >>>>>> >>>>>> tnom = 27 >>>>>> temp = 27 >>>>>> method = trap >>>>>> totiter = 6 >>>>>> traniter = 0 >>>>>> tranpoints = 0 >>>>>> accept = 0 >>>>>> rejected = 0 >>>>>> matrix size = 17 >>>>>> fillins = 0 >>>>>> solver = Normal >>>>>> Matrix Compiler1: 32 opcodes >>>>>> Matrix Compiler2: 967 bytes object code size >>>>> That is so-o-o-o-o useful. WTF does that mean? Does it work, or not? >>>>> >>>> Nope. This was the error message LTSpice let off. >>> Huh? What does... >>> >>> "Direct Newton iteration for .op point succeeded." <<<<<< >>> >>> ... mean? >>> >> Nothing in this case because LTSpice stopped. Plus it normally never >> opens such message windows unless it is unhappy with something. The >> usual waveform window never opened and that's a clear sign that it ain't >> happy. > > Nope. It means that it DID find the OPerating point. >
But no workie.
> You probably don't have the .AC set up properly. I've just posted > another pass.
So how come other opamp model work fine with exactly the same setup? -- Regards, Joerg http://www.analogconsultants.com/
Jim Thompson wrote:
> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> > wrote: > >> Folks, >> >> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >> that I'll ask here instead of the LTSpice group: >> >> I want to do some noise simulations, for example with a TI opamp in >> there. Loading the complete model it spends forever in the stepping >> phase, then pseudo-damped analysis and whatnot. >> >> Is there any way this can be sped up? All I need to see is ballpark >> where the 1/f knees will be with various circuit constellations, input >> current noise, input voltage noise, stuff like that. > > See... > > http://www.analog-innovations.com/SED/Greenshot_2013-01-05_09-42-15_Joerg_Noise.png >
That's what I get with the other opamps (in my case nV/rtHz because that's what I want). I guess the model works in PSpice but for some reason it doesn't in LTSpice -- Regards, Joerg http://www.analogconsultants.com/
On Sat, 05 Jan 2013 12:20:23 -0800, Joerg <invalid@invalid.invalid>
wrote:

>Jim Thompson wrote: >> On Fri, 04 Jan 2013 11:23:55 -0800, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Folks, >>> >>> Yahoo has made the sign-in procedure so onerous (can't get in anymore) >>> that I'll ask here instead of the LTSpice group: >>> >>> I want to do some noise simulations, for example with a TI opamp in >>> there. Loading the complete model it spends forever in the stepping >>> phase, then pseudo-damped analysis and whatnot. >>> >>> Is there any way this can be sped up? All I need to see is ballpark >>> where the 1/f knees will be with various circuit constellations, input >>> current noise, input voltage noise, stuff like that. >> >> See... >> >> http://www.analog-innovations.com/SED/Greenshot_2013-01-05_09-42-15_Joerg_Noise.png >> > >That's what I get with the other opamps (in my case nV/rtHz because >that's what I want). I guess the model works in PSpice but for some >reason it doesn't in LTSpice
Parasitics not properly included in the faulty engine?