TI And Cadence Make PSpice Free

We like simulation software. Texas Instruments long offered TINA, but recently they’ve joined with Cadence to make OrCAD PSpice available for free with some restrictions. You’ve probably heard of PSpice — it’s widely used in academia and industry, but is usually quite costly. You can see a promotional overview video below.

The program requires registration and an approval step to get a license key. The downloaded program has TI models along with other standard models. There seem to be few limits as long as you stick to the supplied library. According to the datasheet, there are no size or simulation complexity limitations in that case. If you want to use other models, you can, but that’s where the limitations hit you:

There is no limitation of how many 3rd party models can be imported into the design. However, if 3rd party models are imported, a user will be able to plot a maximum of 3 signals at a time of their choice when any 3rd party model is imported from web.

We aren’t completely sure what “from web” means there, but presumably they just mean from other sources. In any event, you still get AC, DC, and transient analysis with plenty of options like worst-case timing analysis. Mixed signal designs are supported and there is a wealth of data plotting options, as you would expect.

This is a great opportunity to drive some serious software that is widely used in the industry. The only thing that bummed us out? It runs under Windows. We couldn’t get it to work under Wine, but a Windows 10 VM handled it fine, although we really hate running a VM if we don’t have to.

Still, the price is right and it is a great piece of software. We also liked the recent Micro-Cap 12 release, but we don’t expect any updates for that. Of course, LTSpice is quite capable, too.

23 thoughts on “TI And Cadence Make PSpice Free

  1. “We couldn’t get it to work under Wine, but a Windows 10 VM handled it fine, although we really hate running a VM if we don’t have to.”

    The future is virtualization. Embrace it.

      1. Why virtualize Linux? Linux should be the host, Windows * the “guest”. This means Windows can’t:

        -Damage your hardware through sloppy programming
        -Damage your personal files, through bugs, or malware
        -Gather your personal information
        -Exfiltrate your data

          1. Took me all of 10 clicks or so to virtualize Windows 10 on Linux. I put it on a crap HDD that I don’t care about, and gave it 8/32gb, and 4/8 cores.

            it runs fine enough, it has no network access, and no access to real hardware. I boot it 1-2 times a year to submit my taxes, and thats about it. it gets wiped and reinstalled when complete.

    1. Ew, no. The future should be platform agnostic languages and toolchains so we don’t have these ridiculous arbitrary limitations in a world that’s increasingly moving away from Windows desktops to a more varied array of devices and operating systems.

      Putting an entire OS in a VM just to run a single program is madness.

      1. C and its derivatives were supposed to be platform-agnostic. It doesn’t really work. There is a great open-source DAW (whose name I can’t recall now), there is Linux version freely available and Windows version locked behind a paywall to support development. Or one can download the source and compile it under Windows. One person even succeeded, with help from devs…

        Java is cross-platform. Python is too. There was a game engine written in Java, with two games that were quite good: Chrome and Xpand Rally. Also Minecraft runs on Java. And it runs better on Linux. As for Python, I find it overused and slow in comparison to Java…

        1. Java is the future! With just a few cores [ as few as four], and a little RAM [ as little as 8Gb ] java 4programs like “hello world” can compile and execute in just minutes! Each iteration of the program will get faster, as it runs, as long as it’s kept in memory for optimum performance. With just a little more RAM [ as little as 16GB ] , and 4 more cores, Java programs have as little as 25% user input drop! User time is free!

          Dropping features like IEEE-754 compliance, means your results will be there faster! remember, in math class, you got extra points if you answered quicker, you can always refine the answer later!

          With just a few hundred GB of “helper libraries”, and compatibility applications, most java applications can “just work”, all you have to do is find the correct interpreter, the correct version of the helper libraries for that interpreter, a few hundred gb of disk space, and just a little patience. That ‘hello world’ app can compile and run in just minutes!

          slow languages like ASSembly, and C/C++ are just too slow. The next OS you will be running will be java based. Once your computer boots up in a few weeks, it will be fast as lightning! Moving the mouse will only take 2-3 seconds of latency, but will be super secure!

          Everyone has a UPS, so there will be no need to reboot, since Java can be recompiled on the fly!

      2. Windows stuff is largely moving to .NET so it runs in a VM. It could be multi-platform if Microsoft wanted to release their gui libs or if programmers chose a different gui like GTK or QT.

        A large portion of Linux software and other OSS is Python so it’s interpreted and often actuall is multi-platform.
        Not to mention all the web based software that runs in javascript.

        And I guess somebody still uses Java.

        It’s definitely an easier time to be a programmer with all this high level stuff.
        And with hardware so fast and memory so large the user doesn’t care.

        But how much more electricity are we using as a result?
        What are we doing to the planet?

        Maybe we should program like resources still matter.

    1. It’s ALREADY crippled. “Free with some restrictions” – what could go wrong? Oh – the big restriction is that you can’t use but a few non-TI parts in any given circuit. How useful is that? How many times do we have to have this discussion? “Free” versions of commercial software ARE NOT FREE.

      1. It’s FREE as in beer. It’s BEER which is free, but contains preservatives, which is bad. But it’s FREE, but the preservatives cause CANCER, which is BAD, but it’s FREE which is good, but the carton will set your home on fire, which is BAD.

  2. I find it a bit strange that I seldom see anyone mention ngspice when discussions of SPICE simulation software comes up. My preference for ngspice is based on a lot on cost (hey, I’m a cheap old retired guy at this point so it’s important) but I find it very capable. I have used a fair number of SPICE versions over the last 30 years both professionally and as a hobbyist and I find ngspice to be capable. It does not have a schematic capture front end built in but there are a number of such add-ons if you want to go that way.

    Many of the SPICE versions have minor differences in model parameters: ngspice is pretty mainstream in that regard. I like that ngspice has a scripting language which helps when I am attempting a more involved analysis: the script language allows me to keep a record of what I am doing and easily repeat the analysis. An additional bonus is that I can run it under either Linux or Windows.

    There is a relatively new simulation software qucs which looks interesting and which is not a direct derivative of the original Larry Nagel SPICE. Not had a chance to try qucs yet but now that I am retired it’s on my to-do list. As RoGeorge mentioned there are a lot of RF goodies in qucs that look very interesting.

    For young engineers/hobbyist it appears that we now have a lot of free options: ngspice, PSpice, Opus, qucs, xyspice and likely others. It’s amazing what software is available now.

    The one piece missing is models. I have collected component and subsystem models from wherever I can find them. I find it is not unusual to have to tweek/modify models to mate up with the simulator you choose so I don’t have problem with PSpice having some model specific issues.

    Mark Walter

  3. * Here is what looks like a fairly comprehensive PSpice tutorial. The one big thing that seems to be missing from the tutorial is how to add a custom symbol to a third-party model. But to be fair I don’t now if PSpice even has a symbol editor. If it doesn’t, it should. Other things I’m not seeing are thermal sweeps and Monte Carlo analysis:

    http://www.uta.edu/ee/hw/pspice/index.php

    * Then there is the PSpice User Community:

    “PSpice.com is a PSpice User Community, an open platform dedicated to PSpice Spice circuit simulation discussions” (says Wikipedia).

    * “We couldn’t get it (PSpice) to work under Wine…” That is a bummer. FYI: LTspice works OK in Wine by intent. Or if your machine has the muscle, run PSpice in a Windows VM.

  4. There certainly are a lot of free and even some open source options in this area already.

    But I take it this is a common package for the pros to use?

    So is it better than the various free offerings? Is the simulation more accurate? Or are there some features the free ones just don’t have? I’m not trying to be negative about PSpice. I’m trying to ask the useful questions. The article kind of sounds like an invitation to go find these things out ourselves but if we do that we don’t need to read here. Instead give us a review!

    Actually.. a review would be good to read but not as useful as it could be without something to compare to. How about a series of reviews on simulators similar to the one a while back on popular PCB packages?

  5. The main advantage here is this: TI supplies its high-fidelity spice models only in encrypted PSpice format. This is most likely a conscious decision to protect their IP.

    While LTSpice has decent performance and a superb result viewer, its lack of encrypted model support sometimes makes it worth resorting to PSpice to get a good simulation before designing a part in. That said, I view PSpice as something better used for getting a high accuracy sim on a specific part, rather than doing a fast sim on an overall system.

    Let’s be honest though- the biggest advantage is not having to deal with the large amount of time that it takes to get PSpice setup in an average company. It generally takes a month or two to deal with the salesmen, get the software approved and getting IT to setup a license server. I have no idea why Cadence’s sales and license management is still 20 years in the past.

  6. Why is it such a PITA importing 3rd party models to PSPICE? Followed the only tutorial I could find – it was overly complicated and still didn’t work. Help file was no help at all.
    With Simetrix I just drag the model text file into the command window, and everything happens automagically.

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