PSpice model for OPA140?

Rick,

Here's our interim OPA140 PSpice model. It is working pretty well for most PSpice users at this time,

Thomas

PA - Linear Applications Engineering

Thomas,

I tried this in my old Version 8 MicroSim PSpice, and it does not work.  Here is the portion of the output file where it seems to have failed:

**** EXPANSION OF SUBCIRCUIT X_U1.XIn11 ****
.MODEL X_U1.XIn11.DVNF D KF {PWR(0.001,0.5)/1E11} IS 1.0E-16
X_U1.XIn11.I1 0 X_U1.XIn11.7 10E-3
X_U1.XIn11.I2 0 X_U1.XIn11.8 10E-3
X_U1.XIn11.D1 X_U1.XIn11.7 0 X_U1.XIn11.DVNF
X_U1.XIn11.D2 X_U1.XIn11.8 0 X_U1.XIn11.DVNF
X_U1.XIn11.E1 X_U1.XIn11.3 X_U1.XIn11.6 X_U1.XIn11.7 X_U1.XIn11.8 {PWR(
+ 0.001,0.25)*0.1/1164}
------------------------------------------------------------------$
ERROR -- Invalid number


**** EXPANSION OF SUBCIRCUIT X_U1.XVn11 ****
.MODEL X_U1.XVn11.DVN D KF {PWR(1,0.5)/1E11} IS 1.0E-16
X_U1.XVn11.I1 0 X_U1.XVn11.7 10E-3
X_U1.XVn11.I2 0 X_U1.XVn11.8 10E-3
X_U1.XVn11.D1 X_U1.XVn11.7 0 X_U1.XVn11.DVN
X_U1.XVn11.D2 X_U1.XVn11.8 0 X_U1.XVn11.DVN
X_U1.XVn11.E1 X_U1.XVn11.3 X_U1.XVn11.6 X_U1.XVn11.7 X_U1.XVn11.8 {PWR(
+ 1,0.25)*18/1164}
------------------------------------------------------------------$
ERROR -- Invalid number

Not sure I understand what what is the wrong number.

Can it be fixed?

Thanks.

Hi John,

We'll I am surprised with this result. Unfortunately, I don't have Cadence and it would take a great deal of time to figure this out. The version that will be released in about two months is designed to be universally compatible with many PSpice-based simulators. The current model does run with TINA Spice, TopSpice (see below) and I believe LT Spice.

Regards, Thomas

PA-Linear Applications Engineering

Hi Thomas,

     I got the OPA140 spice model running in PSPICE.  It seems to work fine but only with symmetrical supplies (+/-5, +/- 10,  etc).  If the supplies are not symmetrical PSPICE can't even find a bias point to start at.  Power supply stepping aborts at ~ 40%.  I would like to run the OPA140 between +22,-5 supplies.  Its not supposed to know where ground is.

       Thanx...

Hi John,

Can you send me a picture of the OPA140 circuit you are simulating in Cadence PSpice? I will try it with my TopSPICE and see if I can recreate the asymmetrical power supply issue you have encountered.

Regards, Thomas

PA - Linear Applications Engineering

Hi Thomas,

                Thanx for getting back to me.  Here’s the circuit.  Nothing could be simpler.  I found if I make the supply voltages different by even 1 mV it won’t find an operating point.  I have tried GMIN stepping and power supply stepping.  I’ve attempted to set some IC on some nodes.  I think I’ll try to run it in LT spice.  If it won’t run I think it might at least tell me what the problem is.

7271.OPA140 test.pdf

There must be a better way to include pictures?

Hi John.

The generic OPA140 PSpice model that I sent you didn't have any problems running with my TopSPICE program. The supplies were set to +21/ -5 V. It is didn't hesitate in the least to simulate so this issue seems to be more specific to Cadence. You can see the result I received below (sorry about the small images). The best way to include pictures on this forum is as a file attachment.

I am pretty certain we tried running the model in LT-Spice and it was okay. I know you were originally having problems with the model in Cadence and I am curious what changes you had to make to get it to run with the symmetrical supplies. It sounds like the solution may be marginal if changing the supplies just a few millivolts means the difference between simulating and not simulating.

Regards, Thomas

PA - Linear Applications Engineering

Hi Thomas,

I don't think you sent me a "generic OPA140 spice model".  The one I'm using is the "OPA140 PSpice model" I got from http://www.ti.com/product/OPA140.  Is that the right one?  I find that LT spice is a bit more forgiving but still, if the assemetry is more than a few volts it won't start.  Under LTspice It will run with +21/-18.5.  It won't run with +21/-18.  Unlike PSPICE LTspice never gives up.  It keeps trying to find a starting point. 

Hi John,

Sorry for the confusion over my Spice terminology. The OPA140 model I sent you is one that we have been working on that is more compatible with a number of Spice simulators. Cadence Spice and TopSPICE (which I am using) are very close in terms of syntax compatibility. TopSPICE strives to have their simulator run Cadence syntax which goes has its roots back to Orcad and Micorsim. Oddly though, TopSPice whizzes through the asymmetrical supply simulation without any problem. Different simulators use different convergence algorithms and some come to solution more easily than others with a particular model. Please do note that the OPA140 model is very complex, modeling most of the device's electrical characteristics. It can be a challenge for simulators.

I'll continue to look for a soultion.

Regards, Thomas

PA - Linear Applications Engineering

Hi Thomas,

I don't think you sent me a model.  The one I'm using is this one:  8233.sbom493.zip.  I fetched it from http://www.ti.com/product/OPA140.  Are you refering to another?

          Thanx

Hi John,

Please contact me at my email address (kuehl_tom@ti.com). We'll handle this off the forum.

Thnaks, Thomas

PA - Linear Applications Engineering