How to simulate complex analog power and signal-chain circuits with PSpice for TI


(Note: Bob Hanrahan co-wrote this article.)

Hardware engineers are often expected to deliver results while on tight project timelines. Circuit and system designers must use all of the tools at their disposal to create accurate, robust designs that work well the first time. Those demands, coupled with today’s dynamically changing work environments, mean that tools that you can use at home or remotely for circuit simulation and verification are more valuable than ever before.

Here at TI, we've seen that engineers are reducing the prototyping and evaluation phase of designs; in some cases, they are moving straight to a final printed circuit board (PCB) – yet everyone wants to reduce the risk of circuit errors. To that end, we identified a growing need for a high-performance, full-featured analog simulation platform. So together with Cadence, TI has launched PSpice® for TI, a full-featured version of the industry-standard OrCAD PSpice environment, which makes it easier to simulate entire subsystems for component evaluation and verification.


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Download the new PSpice for TI circuit simulator at no cost

First, why use SPICE simulation?

Simulation program with integrated circuit emphasis (SPICE) has been helping engineers solve hardware design problems for decades. Circuit simulation has three primary use cases:

  • Device evaluation. It is possible to measure the performance of specific products in specific applications, sometimes even before real devices or application circuits are physically available.
  • Design verification. Building and simulating complex board- and system-level designs before building physical prototypes gives engineers confidence in their circuits and reduces design time. Design verification includes the ability to simulate circuit operation in worst-case conditions, ensuring proper operation if parameters such as temperatures, voltage extremes and device tolerances shift after product release.
  • Design debugging. When things don’t go as planned, engineers often turn to simulation to troubleshoot problems or vulnerabilities in their system. Instead of reworking and testing real PCBs, a SPICE simulation can find and initially test circuit fixes.

Leveraging the power of circuit simulation for any or all of these tasks using PSpice for TI helps you reduce development times and get to market faster. There are also inherent benefits to simulation given its computer-based nature. For example, now that working from home is more common, using simulation means that you can make significant progress from anywhere on your projects. There’s also no waiting for parts, PCBs or lab equipment – just build your simulation test bench and go.

You can electronically share circuit simulations easily with other team members for larger system-level simulations or peer-design reviews. You can also run more complex tests such as parametric or temperature sweeps, sensitivity analyses, or device tolerance analyses in ways that would be costly and time-consuming to perform in the real world.

Let's look at an example of this in PSpice for TI. The simulation set up in Figure 1 plots the AC transfer function of a single-pole resistor-capacitor filter network while stepping the value of the capacitor.

PSpice for TI circuit simulation settings showing parametric sweep and AC sweep/noise

Figure 1: PSpice for TI schematic and simulation profile example

Figure 2 shows the resulting plots, along with automatic measurements of each plot’s -3-dB bandwidth and gain at f = 1 MHz. This powerful analysis capability can greatly expedite design optimization.

 PSpice for TI measurement results for AC sweep

Figure 2: PSpice for TI simulation and measurement results

An important note is that proper simulation results assume the device models are accurate and they converge (which in this context means to arrive at an answer) quickly. Thankfully, TI has some of the most accurate and convergence-friendly models in the semiconductor industry, and is continuously working to develop new models and improve its overall modeling capabilities.

Why use PSpice for TI?

PSpice for TI provides both schematic capture as well as analog circuit simulation. Far from being a limited trial, it harnesses many of the advanced features found in the commercial version of the tool, including automatic measurements and post-processing, as well as Monte Carlo and worst-case analysis. PSpice for TI is built on the latest PSpice release, works when offline, is compatible with projects developed in the commercial version, and offers an unlimited number of nodes and measurements when using TI devices.

Speaking of TI devices, along with a standard suite of component models, the complete library of nearly 6,000 TI analog power and signal-chain models is fully integrated into PSpice for TI, enabling you to add TI parts to your projects with just a few clicks. There’s no need to manually import TI models, and the rapidly growing library will automatically update to stay current with what’s available on TI.com.

Most TI device models come with a fully tested and operational design example, and in many cases, a complete reference design from which you can cut and paste. This is a great way to quickly get started with a design and rapidly see device operation and performance. You can place a component and open a related reference design with just a few clicks in the tool. Figure 3 shows an example of just one such design example that is ready for modification and simulation. The figure also shows the application’s new dark mode and customizable color scheme, which reduces energy use and may help reduce eye strain. 

INA293A1 PSpice for TI model for circuit simulation

Figure 3: TI device reference design example

To further help you make quicker design decisions, the tool provides easy access to TI product details and data sheets, and relevant queries for support from the TI E2E™ support forums. A library of tutorial videos is also available within the environment.

To add SPICE simulation to your engineering workflow, download PSpice for TI and start reducing your design time, along with the community of engineers already making use of this powerful tool.

 

Additional resources

  • Find reference designs leveraging the best in TI technology to solve your system-level challenges.
  • Start a new power-supply design with in-depth calculations of voltages and currents using the Power Stage Designer™ software tool.
  • Explore the TI Precision Labs video training curriculum for analog signal-chain design, from foundational knowledge to advanced concepts.
  • Download WEBENCH® Power Designer, a popular, free online power design tool that takes basic input and output specifications and quickly provides a full schematic and bill of materials (BOM).
  • Explore TINA-TI™, a flexible SPICE-based simulation platform that supports a broad range of components, yet maintains a basic user interface sufficient for many analog designs.

  • Hi Ian,

    My I know can we use 3rd party PSPICE models in this PSPICE for TI or only TI PSPICE Models will work.

    Regards

    Hari

  • Hello Hari, you can absolutely use 3rd-party models in PSpice for TI. Under the Tools menu there is an option to "Generate Part." This is where you can import a 3rd-party model netlist and create a symbol. There is also a large library of primitive and parameterized models you can use as well.

  • HI Ian..may I know the difference between TINA and PSPICE for TI.

  • Hi Hari, they are both similar in that they are both SPICE-based circuit simulators. However the workflow to create and simulate circuits is quite different between them. PSpice for TI is based on the latest version of Cadence so it takes many of Cadence's features. In PSpice for TI you can create projects with multiple schematics, simulation profiles, and model libraries. You can also use advanced analysis techniques such as Monte Carlo and Worst-Case analysis. Projects made in PSpice for TI are fully compatible with the full version of Cadence.

  • Hi Ian,

    after working with SPICE simulations for about 30 years I have large libraries with self-written macro-models based on the standard SPICE 3F5. Because of some different syntax details, I think it is clear that I would have to adopt these models before they would run under PSpice for TI. But now my question: Will PSpice for TI treat these models as third-party models (with consequences like allowing only three output signals etc.)? That would be a severe limitation for working. What should I exSpect?

    Regards

    Hans-Juergen

  • Hello Hans-Juergen,

    You may not have to adapt your existing models in standard 3F5 SPICE to work with PSpice. PSpice is an extension of pure Berkeley SPICE, so it should support anything supported by 3F5 SPICE.

    PSpice for TI will recognize these as third-party / unsigned models, so you will encounter some limitations. Just to be clear, you can have an unlimited number of nodes, inputs, and outputs. However you can only probe three nodes at a time. I hope this helps clarify things for you.

  • Hi Ian,

    thank you for your quick response.

    Concerning the SPICE 3F5 compatibility, I have to admit, that I did not get in touch with PSpice for many, many years. But from the past I remember that PSpice was based on Berkeley SPICE 2 and got some extensions e.g. for macro modeling. But PSpice did not follow the step towards Berkeley SPICE 3. That means, that especially the B-sources, which came with Berkeley SPICE 3, were not supported in PSpice – they use extensions of the controlled sources with E = …or I = ... instead.

    In nearly all of my self-written models I used B-sources and some other special modeling syntax from the simulator I use. It is ICAP/4 from Intusoft – a powerful tool. Unfortunately, it fails when I have to use some encrypted models, from TI or others, and here is the reason why I think about PSpice for TI.

    Coming back to the B-sources: May I understand your answer, that PSpice has extended it’s syntax somewhere in the recent years in order to „understand“ the B-sources and other SPICE 3 stuff? That would make life much easier for me.

    Another question: What will happen, if I would write inside PSpice for TI a completely new macro model using the original PSpice syntax? Will this model be treated as a 3rd-party/unsigned model with the limitations you mentioned?

    Best Regards

    Hans-Juergen

  • Hello Hans-Juergen, that is a good point. B sources to my knowledge are not supported in PSpice. However you can achieve the same functionality by using other controlled sources (like E or G) which are set by a VALUE = expression.

    For your second question - if you create your own models and use them in PSpice for TI it will be treated as a 3rd-party model. Only models which are released and signed by TI, or built-in PSpice models, prevent the limitations.

  • Hello Ian,

    thank you for your clear answer – B sources are not supported by PSpice for TI. OK – it means for me, after having to translate lots of models coming in PSpice code to SPICE 3 code over the last decades, now the time has come to go the opposite way.

    Just another question: For simulation TI supported for a lot of years TINA TI, a special version of the TINA simulator. From the user’s point of view, I realise that TINA-TI has not been updated to the latest TINA version (TINA: V12, TINA-TI: V9.3) for some time, and now TI jumps to PSpice for TI. What does that mean? Is it a change in strategic planning? Will TI drop TINA-TI, or will TI support two simulation platforms in parallel?

    Best Regards

    Hans-Juergen

  • Hello Hans-Juergen,

    There is no plan to drop TINA-TI. It will continue to be available and supported. We are simply adding PSpice for TI as a new, powerful option for our customers.