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LTSpice: Slow on noise sims with foreign opamps

Started by Joerg January 4, 2013
Joerg a �crit :
> 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? >
Hey Joerg, are you the Bear of spice ?-) -- Thanks, Fred.
On Sat, 05 Jan 2013 22:38:21 +0100, Fred Bartoli <" "> wrote:

>Joerg a &#2013265929;crit : >> Jim Thompson wrote: >>> On Sat, 05 Jan 2013 08:42:30 -0800, Joerg <invalid@invalid.invalid> >>> wrote:
>> 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? >> > >Hey Joerg, are you the Bear of spice ?-)
I am not sure many know just how funny that is.
Fred Bartoli wrote:
> Joerg a &#2013265929;crit : >> 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? >> > > Hey Joerg, are you the Bear of spice ?-) >
Ursus simulatorus? :-) -- Regards, Joerg http://www.analogconsultants.com/
On Sat, 05 Jan 2013 12:18:27 -0800, Joerg <invalid@invalid.invalid>
wrote:

>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?
Ya got the set-up wrong. ...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 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
I'm still betting there's two possibilities... pin order wrong, or .AC set-up wrong. ...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 12:18:27 -0800, Joerg <invalid@invalid.invalid> > wrote: > >> 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? > > Ya got the set-up wrong. >
That doesn't explain why the other opamps work just fine. -- Regards, Joerg http://www.analogconsultants.com/
On Sat, 05 Jan 2013 16:05:23 -0800, Joerg <invalid@invalid.invalid>
wrote:

>Jim Thompson wrote: >> On Sat, 05 Jan 2013 12:18:27 -0800, Joerg <invalid@invalid.invalid> >> wrote: >> >>> 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? >> >> Ya got the set-up wrong. >> > >That doesn't explain why the other opamps work just fine.
Show me the setups... maybe the pin order is doing you in? ...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 17:10:20 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Sat, 05 Jan 2013 16:05:23 -0800, Joerg <invalid@invalid.invalid> >wrote: > >>Jim Thompson wrote: >>> On Sat, 05 Jan 2013 12:18:27 -0800, Joerg <invalid@invalid.invalid> >>> wrote: >>> >>>> 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? >>> >>> Ya got the set-up wrong. >>> >> >>That doesn't explain why the other opamps work just fine. >Show me the setups... maybe the pin order is doing you in? > > ...Jim Thompson
Looks like LTspice order, for OpAmp2 symbol is... IN+ IN- V+ V- Vout ...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 17:10:20 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >> On Sat, 05 Jan 2013 16:05:23 -0800, Joerg <invalid@invalid.invalid> >> wrote: >> >>> Jim Thompson wrote: >>>> On Sat, 05 Jan 2013 12:18:27 -0800, Joerg <invalid@invalid.invalid> >>>> wrote: >>>> >>>>> 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? >>>> Ya got the set-up wrong. >>>> >>> That doesn't explain why the other opamps work just fine. >> Show me the setups... maybe the pin order is doing you in? >> >> ...Jim Thompson > > Looks like LTspice order, for OpAmp2 symbol is... > > IN+ IN- V+ V- Vout >
Hmm, the OPA model is -IN +IN V- V+ Vout. Is that customary at TI, or in the old Burr-Brown world? If so the I should make a OpAmp2TI or something. -- Regards, Joerg http://www.analogconsultants.com/
Jim Thompson wrote:
> 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 > > I'm still betting there's two possibilities... pin order wrong, or .AC > set-up wrong. >
Looks like pin order (the one you initially suggested as well as the one the OPA model has), thanks for the hint. But now SWMBO wants me to start the barbecue. Pizza over charcoal, in the Weber, yummmm. With lots of Jalapenos on there. Those burn twice ... -- Regards, Joerg http://www.analogconsultants.com/