OPA1612: PSpice model for Altium

Hi Danilo,

I imported the OPA1612.LIB in LTSpice simulation tool, it works fine. So I assumed that there are likely no issues with the model. 

We are supporting Cadence PSpice simulation now. Unfortunately, I do not have Altium simulation tool loaded in my PC. 

https://www.ti.com/tool/PSPICE-FOR-TI

Best,

Raymond

Hi Danilo,

I will provide a first response to your question, but others who are more familiar with Altium's simulation capabilities may be able to provide a more complete answer to your question why you are having a problem.

We build our modern Precision Amplifiers op amps such as the OPA1612 to be Cadence Pspice and TINA Spice compatible. Therefore, the syntax has to work with those simulators. When I review the on line information about Altium's simulator compatibility it states on one of their web pages "The PSpice® simulation model format is the format of choice for many device manufacturers. Altium Designer's Mixed-Signal Circuit Simulator has strong support for PSpice models."  See:

techdocs.altium.com/.../Support for PSpice Models in Altium Designer

I have another PSpice compatible simulator called TopSPICE that is Cadence PSpice syntax compliant. I just ran the OPA1612 model in that simulator and it simulated without issues.

There may be some syntax formats, or statements, that are unique to Altium's simulator. Even though many simulators are in general PSpice compatible, they often have some unique syntax characteristics that keep a user tied to that specific simulator. Maybe the Altium link I provided will offer some clues why the model isn't running.

Regards, Thomas

Precision Amplifiers Applications Engineering

Danilo,

So between Raymond and my results they assure us that it is fully Pspice compliant. It must be something unique to Altium's syntax requirements.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hello. I am the person who was asking for info as to what file to use for simulation of the OPA1612 in Altium, In the downloaded zip file there are many files. Please note that I already have a schematic symbol and footprint for the part. I just need to attach a simulation file/model. I don't need to import the whole library part, just the PSpice file. So I have been asking, which file in the sbom396d.zip file is the PSpice file I need to associate with the OPA1612?

Regards,.

Mike Lacroix

Hi Mike,

The Rev. D is the latest PSpice revision for both OPA161x op amps. We download the model under the same link. If we use Tina simulation tool, then we choose the Tina-TI Spice model, but it will be the same revision. 

https://www.ti.com/product/OPA1612#design-development

Best,

Raymond

Hello Raymond;

I downloaded the PSpice file (general PSpice version). I want to know which file in the downloaded zip file is the PSpice file. Does it have a specific extension like .sim or some other extension.  Or. can someone email me the actual PSpice file only. I am finding it frustrating that someone at TI can't provide me with the name of the PSpice file.

Mike

Hello Thomas:

T;he following lines in the .cir file are not correct for the OPA1612. In the OPA1612 the pinout is as follows;

Pin1 - OUT Channel A, Pin 2 - -IN Channel A, Pin 3 - +IN Channel A, Pin 4 is -V, Pin5 - +IN Channel B, Pin 6 - -IN Channel B, Pin 7 - OUT Channel B, Pin 8 - +V. You will see that the pinout order shown below does not represent the pin out of the OPA1612. My schematic symbol has both channels and as such all of the connections to the OPA1612 don't match the .cir file you sent me. Is there any chance that someone from TI can modify the .cir file so that it will work with the OPA11612? It doesn't make sense to build the schematic with 2 OPA1611 parts for simulation and then change the schematic after back to the OPA1612. Any help appreciated.

Regards, Mike

* PINOUT ORDER +IN -IN +V -V OUT
* PINOUT ORDER  3   2   7  4  6
*****************************************************************************
.SUBCKT OPA1612 3 2 7 4 6
D17 9 0 DIN
D18 10 0 DIN
I14 0 9 0.1E-3

Hello Thomas:

I understand. Since it is something that TI won't do I was wondering if you or someone could provide me with the information on how to modify the existing file for a dual version. Obviously It will  require modifying the subckt line to place the pins in the right order. As I am not an expert in PSpice I don't know where in the code it references or relates to the pin order outside of the subckt line. I would assume that it would be necessary to copy the portion of code for the one amp and add that further down the coding. I also assume that it would be necessary to change all of the component designators so that each amp does not get mixed up. And finally the file has a bunch of models at the end of the file and I don't know what they are or if they need alterations. Personally I have used this amp in previous products and it is a great device but my boss still wants me to do a circuit analysis for this project. OR, can  you provide me with some information on where I can get info on how to write PSpice code.

Mike

Hi Mike,

The intention with the single model is that you apply it twice in the circuit where a dual is needed. It would be a very time consuming effort to deconstruct the single model and modify it such that two identical op amps would reside in the same model. The end difference between using two, individual single section OPA1612 op amps used to fulfill the dual op amp function and a newly constructed model containing the two OPA1612 op amps really comes down is how they appear on the schematic, not the electrical performances.

I've tried to illustrate below how two individual op amps, each labeled as OPA1612 are used to represent the functionality of the dual op amp. I was using TopSPICE, which as I mentioned is PSpice syntax compliant.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hello Thomas:

Please accept my appreciation for all of your help. While I understand what you are stating it doesn't make for efficient work. Below is a typical circuit in which uses both channels of a single device. While it may look like 2 separate ICs they are not as my symbol just shows the 2 amps individually for better readability. In this case we didn't do any simulation including the opamps just the filter network. For me to do things with single opamps as you have shown to do the simulation it means I have to go back correct the schematic and insert the proper symbol for the OPA1612 and that is a waste of time and effort.

So you should see why it is better for me if the PSpice file was written for a device with 2 opamps and not just one. In the case above I need the schematic to show the device connected as it would be when laying out the PCB and it is preferred that the same schematic be used for any and all circuit simulation.

I get why TI only creates files for singles and not duals and quads as it takes less time to create the file but in today's world creating files for duals  and quads should really be matter "copy and paste"a and minimal editing. Since this is not something TI does I would like to know if you could provide me with a schematic of the opamp circuitry so I can see how the PSpice file relates to the components in the circuit. If you can I will try to create my own simulation file based on the .cir file you provided to me earlier.

Regards, Mike

Hi Mike,

PSpice model is traditionally created for a single component. I believe that all companies supplied PSpice models are done this way. 

The link below is demonstrating how to convert Tina-TI model into a generic spice model. There are different approaches to bundle multiple components into a black box with pin assignments etc.. Typically this is done via behavior model or something similar to behavior model. Each simulation tool is handle this interface differently. 

https://www.youtube.com/watch?v=QE7jUcWWi5M

We do not supply lower level op amp circuitry to customers generally. As application engineer, we do not have readily access to the lower level schematic either. This is on a need to know basis, unless the information is published in our website or datasheet.  

If you have other questions, please let us know.

Best,

Raymond