Thermal Results Visualization – Ansys SIWave Icepak and Ansys Electronics Desktop Icepak

As a typically mechanical / systems engineer, I am not exactly qualified to go through and list exactly what SIWave does and why you need it for any given situation (shoutout to Aleksandr, our actual expert, whose assistance has been invaluable for my simple example case). However, what I think I have grasped is that SIWave is just one of those Ansys tools where if you need it, you probably really need it. Where this becomes relevant to me is of course in a PCB thermal analysis. DCIR is typically the electrical half of this problem that is within SIWave’s expansive toolkit, though SIWave also contains some very easy-to-use thermal-oriented options for co-simulation with Icepak. I’ll admit that I have tended to somewhat dismiss this on my end, as I am already familiar with a couple more advanced thermal analysis tools, so why wouldn’t I just use these if I wanted to look at the thermal response of A PCB? Despite this, I have recently (begrudgingly) taken a more in-depth look at the thermal side of SIWave, and what I have found is that even if the settings available are a little more simplistic than I might always like, it really is incredibly accessible and provides some nice visualization capability. What’s more, it provides not only an easy path to view your existing thermal results in a full Icepak interface, but also serves as a great starting point if you need to analyze some more complex setups than Icepak.

So, having just been through much of this on my own, it seems like a great opportunity to share some tips and tricks for thermal visualization in both Ansys SIWave and Ansys Electronics Desktop (EDT) Icepak, see where each is strong relative to the other, and then perhaps even share some suggestions for using the SIWave solution as a starting point to take an Icepak PCB simulation to the next level!

To start with, we need a SIWave DCIR project. A DCIR solution is required for providing thermal loads for a thermal solution. I am glossing over this, but basically, you need a PCB definition, a voltage source, and a current source. In the model I borrowed from Aleks, I am using these sources to push some current through one section of my PCB’s power layer and then referencing them to the ground layer. To complete the loop. This means that there are EM losses on both the ground layer and power layer.

For the first simulation, we’ll want to set a baseline temperature for our electrical material properties and make sure the toggle for “Export power dissipation for use in ANSYS Icepak and Mechanical” is enabled.

Now, we can set up an Icepak simulation! As I alluded to, the settings available within SIWave are somewhat primitive, although they do an overall good job of adhering to typical best practices. Our choices are basically using a board model without components and strictly modeling thermal conduction within that board, using a board model with components that includes explicit thermal convection to the environment, manipulating a mesh detail slider bar, and choosing the cooling regime used (natural vs forced convection). For this model, I’ll be using forced convection with surface components and “Detailed” meshing so that I have the most to look at, but obviously the exact settings will vary somewhat depending on your use-case. In 2021R2, the default SIWave-Icepak behavior will be to use EDT Icepak as the solver, however, we can choose to specify “Use Classic Icepak” in the simulation setup window. This determines which version of Icepak we have to use for additional postprocessing in as well, so I will leave “Use Classic Icepak” turned off.

The first method of visualization in SIWave is to simply right-click an Icepak simulation definition in the “Results” window and Display temperature.

This gives us a nice temperature contour on the outer surface of all the solid bodies considered during the simulation. If we stick with the top-down view, we can make use of a nice temperature probe that automatically displays at the mouse location. Once we rotate around into a 3D view with the middle mouse button or other view options, we lose this probe but of course, gain a nice graphical representation of the full geometry.

The second method is to use the View > Temperature Plots toolbar option, which gives us some more flexibility for viewing temperature through each layer.

Most commonly, we will probably be working with the XY cutting plane and then selecting the layer of interest from the drop-down menu so that we can see a plane through the entire PCB. For more precise control, we can also use the slider bar or input the exact plane-normal location to use for plotting.

One of the benefits of this approach is that we can use the other cutting plane definitions to get a cross-section view, along with whatever ECAD board elements we would like to plot. For instance, if we’d like to see more clearly how the temperature varies with depth underneath active components, or around via definitions, we can easily explore this, as in the image below.

Depending on your needs, this may be sufficient flexibility for observing the temperatures of interest, and the smoothly moving cut plane with the slider-bar position is certainly an easy way to get a sense of the board’s behavior. However, SIWave only gives us access to temperature within the solid bodies of our PCB/components, and we can free ourselves from this limitation by moving into EDT Icepak. There are a couple of primary ways to do this – one is to right-click on the Icepak simulation definition in Results and “Open project in Icepak” and the other is to use the same option from the “Results” section of the top toolbar. The more manual method is to directly open the .aedt file that gets generated alongside the SIWave project file.

Much like SIWave, temperatures in EDT Icepak are primarily displayed on cut-planes or object surfaces. Three-dimensional contour plots are also available but tend to be less clear, especially on very thin bodies (like layers of a PCB). For a cut-plane, the most straightforward option is to directly draw a plane or create a new coordinate system (a coordinate system will automatically create the 3 component planes), which can both be done through the top toolbar. 

Personally, I find it easiest to quickly create the objects in the graphical window and then select them in the model tree to fine-tune their locations through the properties display, as above. I do think this is one of the places that SIWave has an edge in ease-of-use – having that slider bar definition for a plane is much nicer. Although, using this method in Icepak also lets us angle the plane however we like, so there are still trade-offs to be considered.

Once we have a plane defined, it is then very easy to select this plane in the model tree and right-click > Temperature > Temperature to create a temperature plot.

One of the immediately observable differences is that we can now view temperature contours throughout the volume of air surrounding our PCB in addition to the PCB itself. So, if we were trying to compare against something like an experimental setup with a thermocouple placed in-air near the board, this would be the way to do it!

If we’re not interested in quite so large of a plot, we can also limit it to a certain model volume by choosing one of the objects in the “In Volume” list of the plot properties. In this case, Box1 and Box2 are smaller volumes enclosing the PCB that were automatically generated for mesh controls, which we can easily reuse for trimming down our temperature plot.

To instead plot on the surface of an object, we can select that object in the model tree (for the whole PCB, it is convenient to right-click it in the tree and use the “Select All” option), follow the same Plot Fields > Temperature > Temperature as before, and then make sure to enable “Plot on surface only”.

This should produce a plot that is very similar to what we obtained in SIwave. Another advantage of doing this in Icepak should now become clear — we have the capability to stack multiple field plots! As below, we can see the solid body surface temperatures alongside our cut plane temperature down the center.

We can get as creative with this as we’d like, plotting on many different cut planes simultaneously, or even combining types of plots. Since we have access to the air volume solution, we can even do things like plot velocity vectors around the PCB for more insight into the overall system.

Having access to the full solution field (fluid and solids) means we can also visualize some other helpful values. The surface heat transfer coefficients can help us understand how to improve our setup in some cases, for instance. In the below plot, we can see some clear shadowing behind surface components which is indicative of the primary flow separating from the surface of the PCB. This certainly explains why the back end of the board is so hot – the components in the back are somewhat hidden from the flow field by those in the front. Since component (and component power) density is higher in the back, we might choose to reverse the direction of flow so that the particularly dense section of components receives the brunt of the airflow, or maybe we might explore angling the board relative to the inlet such that the entire top receives more direct flow.

While we might reach the same or similar conclusions by looking at data through SIWave’s interface, we certainly wouldn’t have access to the tools necessary to actually implement all these changes to the simulation.

As an example, I can pretty easily create a new coordinate system, rotate it by 11° from the original, and then assign my air box to the rotated reference. In effect, this angles all of PCB related volumes with respect to the flow field in just a couple of steps.

After solving, I can then compare the new temperature fields to the old and pretty quickly find that the hotspot on the top surface has been greatly reduced and that the maximum temperature of the system has dropped by about 9 °C. Not too bad! Of course, since I have modified at least one of the simulation bodies, we do have to remesh and solve from scratch, however, we already have an existing DCIR simulation to make use of, and it was much easier getting to this point having started in SIWave.

For my last set of tips, the visualization of the PCB itself in Icepak has been rudimentary so far, but we can also adjust this. Much like in SIWave, we can turn on and off the visualization of features for individual layers independently of anything else. These visualization settings are accessible by selecting our board in the 3D components list and then looking at the properties section.

Since these settings are independent of the 3D geometry visualization, we can selectively hide our model objects in order to isolate the detailed ECAD features. In my test case, the dielectric “Unnamed” layers include via definitions – so I can turn on visualization of these layers, hide the geometry for every layer except the bottom, and plot a temperature cut plane to get a nice visualization of how temperature varies around particular vias.

We could do the same for a temperature cut plane through the width/length of the board as well or even look at heat transfer coefficients on the PCB surface in regions of high via density. As is often the case with Ansys tools, the sky is the limit here.  

In summary, the SIWave interface can be both a great starting and ending point for thermal simulation depending on your needs. It makes setting up a complicated simulation very easy, albeit by removing some user flexibility, but it does allow for several methods of viewing thermal results. These include a smooth slider bar visualization for cut-plane temperatures and a dynamic mouse-probe for checking temperature values in the top-down 2D view. Since SIWave makes use of the full Icepak solver in the background, we can also access a whole lot of additional information by simply opening the existing Icepak solution in the full EDT Icepak interface after a solution has been generated. This gives us access to new thermal solution variables, variables from the fluid portion of our solutions, and new ways to plot and visualize all this information. The combination of SIWave and EDT Icepak also provides us with the opportunity to run an initial set of thermal simulations for relatively simple setups and then build on top of those with more complex boundary conditions or geometry configurations, if we either need greater detail or want to try out some more advanced cooling scenarios.

All Things Ansys 095: High Frequency Electronics Updates in Ansys 2021 R2

 

Published on: August 25th, 2021
With: Eric Miller & Aleksandr Gafarov
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s application engineer and high frequency electronics expert, Aleksandr Gafarov for a look at what’s new for this product offering in Ansys 2021 R2.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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All Things Ansys 093: Introducing Ansys 2021 R2

 

Published on: July 26th, 2021
With: Eric Miller, Tom Chadwick, Aleksandr Gafarov, Joe Woodward, Ted Harris, Sina Ghods, & Josh Stout
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by members of the simulation support team to explore Ansys 2021 R2 and discuss their favorite features so far.

Ansys multiphysics software solutions and digital mission engineering help companies innovate and validate like never before. Ansys gives engineers the power to see how their ideas will perform against millions of variables.

Ansys 2021 R2 delivers significant improvements in simulation technology together with nearly unlimited computing power to help engineers across all industries reimagine product design and achieve product development goals that were previously thought impossible.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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All Things Ansys 092: Recap of Ansys 2021 R1 & Beyond

 

Published on: July 12th, 2021
With: Eric Miller, Tom Chadwick, Aleksandr Gafarov, Joe Woodward, Ted Harris, Doug Oatis & Josh Stout
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by members of the simulation support team to recap Ansys 2021 R1 and discuss expectations and predictions for 2021 R2.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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Welcome to a New Era in Electronics Reliability Simulation

Simulation itself is no longer a new concept in engineering, but individual fields, applications, and physics are continually improved upon and integrated into the toolbox that is an engineer’s arsenal. Many times, these are incremental additions to a particular solver’s capabilities or a more specialized method of post processing, however this can also occasionally be present through new cross-connections between separate tools or even an entirely new piece of software. As a result of all this, Ansys has now reached critical mass for its solution space surrounding Electronics Reliability. That is, we can essentially approach an electronics reliability problem from any major physics perspective that we like.

So, what is Electronics Reliability and what physics am I referring to? Great question, and I’m glad you asked – I’d like to run through some examples of each physics and their typical use-case / importance, as well as where Ansys fits in. Of course, real life is a convoluted Multiphysics problem in most cases, so having the capability to accommodate and link many different physics together is also an important piece of this puzzle.

Running down the list, we should perhaps start with the most obvious category given the name – Electrical Reliability. In a broad sense, this encompasses all things related to electromagnetic fields as they pertain to transmission of both power and signals. While the electrical side of this topic is not typically in my wheelhouse, it is relatively straightforward to understand the basics around a couple key concepts, Power Integrity and Signal Integrity.

Power integrity, as its name suggests, is the idea that we need to maintain certain standards of quality for the electrical power in a device/board/system. While some kinds of electronics are robust enough that they will continue to function even under large variations in supplied voltage or current, there are also many that rely on extremely regular power supplies that only vary above certain limits or within narrow bounds. Even if we’re looking at a single PCB (as in the image below), in today’s technological environment it will no doubt have electrical traces mapped all throughout it as well as multiple devices present that operate under their own specified electrical conditions.

Figure 1: An example PCB with complex trace and via layouts, courtesy of Ansys

If we were determined to do so, we could certainly measure trace lengths, widths, thicknesses, etc., and make some educated guesses for the resulting voltage drops to individual components. However, considerably more effort would need to be made to account for bends, corners, or variable widths, and that would still completely neglect any environmental effects or potential interactions between traces. It is much better to be able to represent and solve for the entire geometry at once using a dedicated field solver – this is where Ansys SIwave or Ansys HFSS typically come in, giving us the flexibility to accurately determine the electrical reliability, whether we’re talking about AC or DC power sources.

Signal integrity is very much related, except that “signals” in this context often involve different pathways, less energy, and a different set of regulations and tolerances. Common applications involve Chip-signal modeling and DDRx virtual compliance – these have to do with not only the previous general concerns regarding stability and reliability, but also adherence to specific standards (JEDEC) through virtual compliance tests. After all, inductive electromagnetic effects can still occur over nonconductive gaps, and this can be a significant source of noise and instability in cases where conductive paths (like board traces or external connections) cross or run very near each other.

Figure 2: Example use-cases in virtual compliance testing, courtesy of Ansys

Whether we are looking at timings between components, transition times, jitter, or even just noise, HFSS and SIWave can both play roles here. In either case, being able to use a simulation environment to confirm that a certain design will or will not meet certain standards can provide invaluable feedback to the design process.

Other relevant topics to Electrical Reliability may include Electromagnetic Interference (EMI) analysis, antenna performance, and Electrostatic Discharge (ESD) analysis. While I will not expand on these in great detail here, I think it is enough to realize that an excellent electrical design (such as for an antenna) requires some awareness of the operational environment. For instance, we might want to ensure that our chosen or designed component will adequately function while in the presence of some radiation environment, or maybe we would like to test the effectiveness of the environmental shielding on a region of our board. Maybe, there is some concern about the propagation of an ESD through a PCB, and we would like to see how vulnerable certain components are. Ansys tools provide us the capabilities needed to do all of this.

The second area of primary interest is Thermal Reliability, as just about anyone who has worked with or even used electronics knows, they generate some amount of heat while in use. Of course, the quantity, density, and distribution of that heat can vary tremendously depending on the exact device or system under question, but this heat will ultimately result in a rise in temperature somewhere. The point of thermal reliability basically boils down to realizing that the performance and function of many electrical components depends on their temperature. Whether it is simply a matter of accounting for a change in electrical conductivity as temperature rises or a hard limit of functionality for a particular transistor at 150 °C, acknowledging and accounting for these thermal effects is critical when considering electronics reliability. This is a problem with several potential solutions depending on the scale of interest, but generally we cover the package/chip, board, and full system levels. For the component/chip level, a designer will often want to provide some package level specs for OEMs so that a component can be properly scoped in a larger design. Ansys Icepak has toolkits available to help with this process; whether it is simplifying a 3D package down to a detailed network thermal model or identifying the most critical hot spot within a package based on a particular heat distribution. Typically, network models are generated through temperature measurements taken from a sample in a standardized JEDEC test chamber, but Icepak can assist through automatically generating these test environments, as below, and then using simulation results to extract well defined JB and JC values for the package under test.

Figure 3: Automatically generated JEDEC test chambers created by Ansys Icepak, courtesy of Ansys

On the PCB level of detail, we are likely interested in how heat moves across the entire board from component to component or out to the environment. Ansys Icepak lets us read in a detailed ECAD description for said PCB and process its trace and via definitions into an accurate thermal conductivity map that will improve our simulation accuracy. After all, two boards with identical sizing and different copper trace layouts may conduct heat very differently from each other.

Figure 4: Converting ECAD information into thermal conductivity maps using Ansys Icepak, courtesy of Ansys

On the system level of thermal reliability, we are likely looking at the effectiveness of a particular cooling solution on our electronic design. Icepak makes it easy to include the effects of a heat exchanger (like a coldplate) without having to explicitly model its computationally expensive geometry by using a flow network model. Also, many of today’s electronics are expected to constantly run right up against their limit and are kept within thermal spec by using software to throttle their input power in conjunction with an existing cooling strategy. We can use Icepak to implement and test these dynamic thermal management algorithms so that we can track and evaluate their performance across a range of environmental conditions.

The next topic that we should consider is that of Mechanical Reliability. Mechanical concepts tend to be a little more intuitive and relatable due to their more hands-on nature than the other two, though the exact details behind the cause and significance of stresses in materials is of course more involved. In the most general sense, stress is a result of applying force to an object. If this stress is high compared to what is allowed by a material, then bad things tend to happen – like permanent deformation or fracture. For electronic devices consisting of many materials, small structures, and particularly delicate components, we have once again surpassed what can be reasonably accomplished with hand calculations. Whether we are looking at an individual package, the integrity of an entire PCB, or the stability that a rigid housing will provide to a set of PCBs, Ansys has a solution. We might use Ansys Mechanical to look at manufacturing allowances for the permissible force used while mounting a complicated leaded component onto a board, as seen below. Or maybe, we will use mechanical simulation to find the optimal positioning of leads on a new package such that its natural vibrational frequencies are outside normal ambient conditions.

Figure 5: A surface component with discretely modeled leads, courtesy of Ansys

At the PCB level, we face many of the same detail-oriented challenges around representing traces and vias that have been mentioned for the electrical applications. They may not be quite as critical and more easily approximated in some ways, but that does not change the fact that copper traces are mechanically quite different from the resin composites often used as the substrate (like FR-4). Ansys tools like Sherlock provide best in class PCB modeling on this front, allowing us to directly bring in ECAD models with full trace and component detail, and then model them mechanically at several different levels depending on the exact need. Automating a materials property averaging scheme based on the local density of traces may be sufficient if we are looking at the general bending behavior of a board, but we can take it to the next level by explicitly modeling traces as “reinforcement” elements. This brings us to the level of detail where we can much more reliably look at the stresses present in individual traces, such that we can make good design decisions to reduce the risk of traces peeling or delaminating from the surface.

Figure 6: Example trace mapping workflow and methods, courtesy of Ansys

Beyond just looking at possible improvements in the design process, we can also make use of Ansys tools like LS-DYNA or Mechanical to replicate testing or accident conditions that an existing design could be subjected to. As a real-world example, many of us are all too familiar with the occasional consequences of accidentally dropping our smart phones – Ansys is used to test designs against these kind of shock events, where impact against a hard surface can result in high stresses in key locations. This helps us understand where to reinforce a design to protect against the worst damage or even what angle of impact is most likely to cause an operational failure.

As the finale for all of this, I come back to the first comment of reality being a complex Multiphysics problem. Many of the previous topics are not truly isolated to their respective physics (as much as we often simplify them as such), and this is one of the big ways in which the Ansys ecosystem shines: Comprehensive Multiphysics. For the topic of thermal reliability, I simply stated that electronics give off heat. This may be obvious, but that heat is not just a magical result of the device being turned on but is instead a physical and calculable result of the actual electrical behavior. Indeed, this the exact kind of result that we can extract from one of the relevant electronics tools. An HFSS solution will provide us with not only the electrical performance of an antenna but also the three-dimensional distribution of heat that is consequently produced. Ansys lets us very easily feed this information into an Icepak simulation, which then has the ability to give us far more accurate results than a typical uniform heat load assumption provides.

Figure 7: Coupled electrical-thermal simulation between HFSS and Icepak, courtesy of Ansys

If we find that our temperatures are particularly high, we might then decide to bring these results back into HFSS to locally change material properties as a function of temperature to get an even more accurate set of electrical results. It could be that this results in an appreciable shift in our antenna’s frequency, or perhaps the efficiency has decreased, and aspects of the design need to be revisited. These are some of the things that we would likely miss without a comprehensive Multiphysics environment.

On a more mechanical side, the effects on stress and strain from thermal conditions are very well known and understood at this point, but there is no reason we could not use Ansys to bring the electrical alongside this established thermal-mechanical behavior. After all, what is a better representation of the real physics involved than using SIwave or HFSS to model the electrical behavior of a PCB, bringing those result into an Icepak simulation as a heat load to test the performance of a cooling loop or heat sink, and then using at least some of those thermal results to look at stresses through not only a PCB as a whole but also individual traces? Not a whole lot at this moment in time, I would say.

The extension that we can make on these examples, is that they have by and large been representative cases of how an electronics device responds to a particular event or condition and judging its reliability metrics based on that set of results, however many physics might be involved. There is one more piece of the puzzle we have access to that also interweaves itself throughout the Multiphysics domain and that is Reliability Physics. This is mostly relevant to us in electronics reliability for considering how different events, or even just a repetition of the same event, can stack together and accumulate to contribute towards some failure in the future. An easy example of this is a plastic hinge or clip that you might find on any number of inexpensive products – flexing a thin piece of plastic like in these hinges can provide a very convenient method of motion for quite some time, but that hinge will gradually accumulate damage until it inevitably cracks and fails. Every connection within a PCB is susceptible to this same kind of behavior, whether it is the laminations of the PCB itself, the components soldered to the surface, or even the individual leads on a component. If our PCB is mounted on the control board of a bus, satellite, or boat, there will be some vibrations and thermal cycles associated with its life. A single one of these events may be of much smaller magnitude and seemingly negligible compared to something dramatic like a drop test, and yet they can still add up to the point of being significant over a period of months or years.

This is exactly the kind of thing that Ansys Sherlock proves invaluable for: letting us define and track the effect of events that may occur over a PCB’s entire lifecycle. Many of these will revolve around mechanical concepts of fatigue accumulating as a result of material stresses, but it is still important to consider the potential Multiphysics origins of stress. Different simulations will be required for each of mechanical bending during assembly, vibration during transport, and thermal cycling during operation, yet each of these contributes towards the final objective of electronics reliability. Sherlock will bring each of these and more together in a clear description of which components on a board are most likely to fail, how likely they are to fail as a function of time, and which life events are the most impactful.

Figure 8: Example failure predictions over the life cycle of a PCB using Ansys Sherlock, courtesy of Ansys

Really, what all of this comes down to is that when we design and create products, we generally want to make sure that they function in the way that we intend them to. This might be due to a personal pride in our profession or even just the desire to maximize profit through minimizing the costs associated with a component failure, however at the end it just makes sense to anticipate and try to prevent the failures that might occur under normal operating conditions.

For complex problems like electronics devices, there are many physics all intimately tied together in the consideration of overall reliability, but the Ansys ecosystem of tools allows us to approach these problems in a realistic way. Whether we’re looking at the electrical reliability of a circuit or antenna, the thermal performance of a cooling solution or algorithm, or the mechanical resilience of a PCB mounted on a bracket, Ansys provides a path forward.

If you have any questions or would like to learn more, please contact us at info@padtinc.com or visit www.padtinc.com.

Signal & Power Integrity Updates in Ansys 2021 R1 – Webinar

The use of Ansys Electronics solutions minimizes the testing costs, ensures regulatory compliance, improves reliability and drastically reduces your product development time. All this while helping you build the best-in-class and cutting-edge products.

With signal and power integrity (SI & PI) analysis products, users can mitigate many electrical and thermal issues affecting printed circuit boards such as electromagnetic interference, crosstalk, overheating, etc. Ansys integrated electromagnetics and circuit simulation tools are essential for designing high-speed serial channels, parallel buses, and complete power delivery systems found in modern high-speed electronic devices.

Leverage the simulation capability from Ansys to solve the most critical aspects of your designs. Join PADT’s Electronics expert and application engineer Aleksandr Gafarov for a detailed look at what is new for SI & PI in Ansys 2021 R1, including updates available within the following tools:

• SIwave – Granta support & differential time domain crosstalk

• Q3D – Uniform current terminals

• Circuits – Network data explorer & SPISim

• HFSS 3D – Parallel meshing, encrypted 3D components & IC workflow improvements

• Electronics Desktop – Ansys cloud, Minerva & optiSLang integration

• And much more

Register Here

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You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!

Electronics Reliability Updates in Ansys 2021 R1 – Webinar

Best practices for ensuring and predicting electronics reliability require comprehensive multi-physics simulations. Ansys ensures reliability success by developing solutions and workflows that overcome today’s biggest simulation and design challenges. 

With Ansys 2021 R1, electronics reliability became much easier to manager with advanced capabilities for design democratization, workflow automation, and robust reliability predictions. Along with these updated components, users can better access integrated workflows between Ansys Sherlock, Icepak, Mechanical, LS-Dyna, and more to provide the results necessary to optimize product designs and ensure unparalleled reliability in the field. 

Join PADT’s Systems Application & Support Engineer Josh Stout for a presentation covering updates to existing features and the introduction of new tools available in this latest release. Learn how users can:

• Extract detailed geometries from any ECAD file

     • Predict time to failure before prototyping

     • Perform complex multiphysics analyses

     • Implement automation and optimization 

     • And much more

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If this is your first time registering for one of our Bright Talk webinars, simply click the link and fill out the attached form. We promise that the information you provide will only be shared with those promoting the event (PADT).

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Thermal Integrity Updates in Ansys 2021 R1 – Webinar

With CAD-centric (mechanical and electrical CAD) and multiphysics user interfaces, Icepak facilitates the solving of today’s most challenging thermal management problems in electronics products and assemblies. Icepak uses sophisticated CAD healing, simplification and metal fraction algorithms that reduce simulation times, while providing highly accurate solutions that have been validated against real-world products.

This tool provides powerful electronic cooling solutions that utilize the industry leading Ansys Fluent computational fluid dynamics solver for thermal and fluid flow analyses of integrated circuits, packages, printed circuit boards, and electronic assemblies.

With the release Ansys 2021 thermal integrity capabilities saw improvements in a variety of areas. Join PADT’s Application & Support Engineer and Thermal Integrity expert Josh Stout to learn more about recent advancements surrounding: 

• Solar Radiation Modeling

     • Robust Meshing Distribution

     • Dynamic Thermal Management

     • The Release of AEDT Mechanical Solutions

     • And Much More

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High Frequency Updates in Ansys 2021 R1 – Webinar

Whether leveraging improved workflows or leading-edge capabilities with Ansys 2021 R1, teams are tackling design challenges head on, eliminating the need to make costly workflow tradeoffs, developing next-generation innovations with increased speed and significantly enhancing productivity, all in order to deliver high-quality products to market faster than ever.

When it comes to high frequency electromagnetics, Ansys 2021 R1 delivers a plethora of groundbreaking enhancements. Ansys HFSS Mesh Fusion enables simulation of large, never before possible electromagnetic systems with efficiency and scalability. This release also allows for encrypted 3D components supported in HFSS 3D Layout for PCBs, IC packages and IC designs to enable suppliers to share detailed 3D component designs for creating highly accurate simulations.

Join PADT’s Lead Electromagnetics Engineer and high frequency expert Michael Griesi for a presentation on updates made to the Ansys HF suite in the 2021 R1 release, including advancements for:

  • Electronics Desktop
  • HFSS
  • Circuits
  • EMIT
  • And Much More

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All Things Ansys 070: Optimizing Electronics Reliability with Ansys Sherlock

 

Published on: August 24th, 2020
With: Eric Miller & Josh Stout
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Application & Support Systems Engineer, Josh Stout for a discussion on the unique capabilities of Ansys Sherlock, and what’s new for the tool in 2020 R2.

If you would like to learn more about this update, you can view Josh’s webinar on the topic here: https://www.brighttalk.com/webcast/15747/428230

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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SPISim – New addition to the Ansys Electronics family

In this article, I would like to introduce some new features added to the Ansys Electronics Solution 2020R2 release called SPISim. Since this is a new tool, I’ll focus on describing its capabilities as well as some possible applications.

What is SPISim?

Signal, Power Integrity and Simulation (SPISim) focuses on system-level and on-chip SI/PI modeling, simulation, and analysis. The tool presents a variety of different features, which are split on separate modules shown below.

Let us look at each module individually and highlight the key functionality.

There are 2 main Modules VPro and MPro. All the other features (sub-modules) are split between these main two.

VPro Core

This is a versatile GUI for viewing waveforms. It supports a wide variety of formats including .tr0, .ac0, .ibis, .csv, .mat, .raw, .snp, .citi, and more. Besides simple viewing capabilities, VPro can also be used for waveform analysis:

  • Overshoot and Undershoot (for Peaks and Valleys)
  • Threshold Crossings
  • Min/Max Peak-2-Peak
  • Root-Mean-Square Value 
  • FFT, iFFT
  • Correlation
  • Pulse to PDA

Using the information about waveforms, this tool can also plot an eye diagram, perform simple correlations, and run measurements. The viewer also supports framework scripting on JavaScript, Ruby, TCL, etc.

DPro Unit (VPro Module)

DPro (short for DDR Pro) provides comprehensive DDR related post-processing analysis. Key functionalities of this tool:

  • Batch mode of processing one or more waveform files
  • Support of multiple receiver processing
  • Built-in and customizable derating table and derating processing
  • Built-in 100+ measurement functions for typical DDR signal analysis
  • Results cross-probing and show problematic location automatically

The feature is organized in a wizard-like style. The user simply needs to fill out information in 6 tabs and click the ‘Run’ button. Overall, it is very intuitive to use, but like any new features, there is a learning curve for a new user.

TPro Unit (VPro Module)

It provides comprehensive transmission line related modeling, analysis, post-processing, and viewing capabilities. Here are several main functionalities offered by this add-on:

  • Comprehensive stackup planner to model t-lines’ performance in different stackup configurations
  • Advanced t-line modeling viewer for rapid analysis such as impedance, crosstalk, or propagation delay analysis
  • A table viewer for RLCG frequency content
  • What-if analysis for quick impedance/crosstalk calculation, and data processing, such as trimming and merging of frequency points
  • Batch mode processing and measurements for one or more t-line model files, result is a plain .csv file ready for further modeling or analysis

This feature helps the user to run pre-layout ‘what-if’ analysis. Both ‘transmission line analyzer’ and ‘layer stackup planner’ give the user a flexible way of understanding potential design constrains and guidelines.

SPro Unit (VPro Module)

This module is similar to TPro in a sense of the capabilities. However, it is directed to view and analyze S-parameters instead of tabular transmission line data. Also, in contrast to TPro, this feature has a separate tab ‘S-Param’ with all the features listed there.

Here are major capabilities of SPro:

  • Advanced s-parameter viewer for speedy analysis such TDR/TDR or PDA analysis
  • Table viewer for frequency content; export s-parameter data to matlab .mat format and more
  • 20+ advanced analysis functions such as mixed-mode conversion, cascading and renormalization
  • Batch mode processing and measurements for one or more s-parameter files
  • Support customizable s-parameter reporting generation for lab automation and beyond

Besides the conceptual similarities with the TPro, S-parameter’s waveform viewer based on VPro waveform viewer. Therefore, all operations available in VPro can also be found in S-parameter viewer.

Signal Generator Unit

This tool allows the user to generate a signal and use it in a future analysis. The generator offers wide variety of signal patterns (such as PRBS, Pulse, Sine, Square, Sawtooth etc) in combination with the PAM4 and NRZ modulation schemes. The user needs only to specify parameters for the signal and then create it.

This simple, but very powerful feature helps to save time for the engineer. 

MPro Core

By definition, MPro is a modeling unit, which helps the user to work with the data. However, modeling can mean different things. The main advantage of MPro is providing the user with the simple environment for data manipulation. Here are all main functionalities of this core module:

  • Table data processing: combine, extract, summarize statistically, etc
  • Plan sampling with design of experiments, full factorial, Monte Carlo, etc
  • Simulate or collect data using customizable scripts, supporting multi-CPU/multi-thread
  • Visualize data in statistical, 2D or 3D plots
  • Model data using response surface modeling, neural network (feed forward and radial basis), etc
  • Optimization using linear, nonlinear, or genetic algorithm methods

BPro IBIS and AMI Unit (MPro Module)

BPro is one unit, however in this description I have purposefully separated it into two – BPro IBIS and BPro AMI, because the functionality of BPro is very broad. It is easier to focus on a one thing at a time.

Generally, BPro brings comprehensive IBIS related modeling, analysis, post-processing, and viewing capabilities to user. In more detail:

  • Has an inspector to view IBIS model’s textual content and visualize various waveform/current table easily. Tool also allows manual editing of model data with a simple mouse click and drag
  • Built-in advanced IBIS model generation flow from either scratch or existing simulation data. Tool will guide user from modeling setup, spice decks generations, simulation, modeling, syntax checking with golden parser, validation to final figure of merits (FOM) reporting
  • Support batch mode generations of performance reports for one or more model files. Results are in .csv file format and can be used for further analysis
  • IBIS model generation from Spec. or data sheet without performing any simulation. Generated model will also have two sets of waveforms under different loading conditions

Under ‘IBIS’ menu tab, the user will find separate sets of commands for both IBIS and AMI, as well as commands for IBIS-AMI in general.

Summary

This new addition to Ansys Electronics Solution brings a very wide variety of features to engineers. All Waveform Viewer, Signal Generator, IBIS-AMI modeling, DDR analysis, Data optimization, and Transmission line planner are united under one tool – SPISim. We can launch this tool either from within Ansys 3D Layout or SIwave, and, in 2020R2, is accessible through the Electronics Enterprise license.

Here is an overview of the SPISIm functionality:

Besides developing the help documentation and video demos, SPISim engineer team provides users with the detailed information about the tool in their blog – http://www.spisim.com/blogs/blog-articles-index/  and helps to fill out the technical ‘gaps’ by sharing the reference material – http://www.spisim.com/products/ami-spisims-ibis-ami/academic-serdes-ami-reference/

If you would like more information related to this topic or have any questions, please reach out to us at info@padtinc.com.

Optimizing Electronics Reliability with Ansys Sherlock – Webinar

Ansys Sherlock automated design analysis software is the only Reliability Physics/Physics of Failure (PoF)-based electronics design analysis software that provides fast and accurate life predictions for electronic hardware at the component, board and system levels in early design stages. A unique, powerful capability of Sherlock is its revolutionary ability to rapidly convert electronic CAD (ECAD) files into CFD and FEA models with accurate geometries and material properties.

Through its powerful parsing engine and embedded libraries containing over 500,000 parts, Sherlock reduces pre-processing time from days to minutes and automates workflows through its integration with Ansys Icepak, Ansys Mechanical and Ansys Workbench.

With its extensive parts/materials libraries, Sherlock automatically identifies your files and imports your parts list, then builds an FEA model of your circuit board in minutes. It also produces a holistic analysis that is critical to developing reliable electronics products. It enables designers to simulate each environment, failure mechanism and assembly that a product might encounter over its lifespan.

Join PADT’s Systems Application & Support Engineer Josh Stout for an introduction to this powerful tool along with a look at what new features and updates have been added in the Ansys 2020 R2 version.

Register Here

If this is your first time registering for one of our Bright Talk webinars, simply click the link and fill out the attached form. We promise that the information you provide will only be shared with those promoting the event (PADT).

You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!

“Equation Based Surface” for Conformal and Non-Planar Antenna Design

ANYSY HFSS provides many options for creating non-planar and conformal shapes. In MCAD you may use shapes such as cylinders or spheres, and with some steps, you can design you antennas on various surfaces. In some applications, it is necessary to study the effect of curvatures and shapes on the antenna performance. For example for wearable antennas it is important to study the effect of bending, crumpling and air-gap between antenna and human body.

Equation Based Surface

One of the tools that HFSS offers and can be used to do parametric sweep or optimization, is “Draw equation based surface”. This can be accessed under “Draw” “Equation Based Surface” or by using “Draw” tab and choosing it from the banner (Fig. 1)

Fig. 1. (a) Select Draw -> Equation Based Surface
Fig. 1. (b) click on the icon that is highlighted

Once this is selected the Equation Based Surface window that opens gives you options to enter the equation with the two variables (_u, _v_) to define a surface. Each point of the surface can be a function of (_u,_v). The range of (_u, _v) will also be determined in this window. The types of functions that are available can be seen in “Edit Equation” window, by clicking on “…” next to X, Y or Z (Fig. 2). Alternatively, the equation can be typed inside this window. Project or Design Variables can also be used or introduced here.

Fig. 2. (a) Equation Based Surface window
Fig. 2. (b) Clikc on the “…” next to X and see the “Edit Equation: window to build the equation for X

For example an elliptical cylinder along y axis can be represented by:

This equation can be entered as shown in Fig. 3.

Fig. 3. Elliptical surface equation

Variation of this equation can be obtained by changing variables R1, R2, L and beta. Two examples are shown in Fig. 4.

Fig. 4. Elliptical surface equation

Application of Equation Based Surface in Conformal and Non-Planar Antennas

To make use of this function to transfer a planar design to a non-planar design of interest, the following steps can be taken:

  • Start with a planar design. Keep in mind that changing the surface shape can change the characteristics of the antenna. It is a good idea to use a parameterized model, to be able to change and optimize the dimensions after transferring the design on a non-planar surface. As an example we started with a planar meandered line antenna that works around 700MHz, as shown in Fig. 5. The model is excited by a wave port. Since the cylindrical surface will be built around y-axis, the model is transferred to a height to allow the substrate surface to be made (Fig 5. b)
Fig. 5. Planar meandered antenna (a) on xy plane, (b) moved to a height of 5cm
  • Next, using equation based surface, create the desired shape and with the same length as the planar substrate. Make sure that the original deisgn is at a higher location. Select the non-planar surface. Use Modeler->Surface->Thicken Sheet … and thicken the surface with the substrate thickenss. Alternatively, by choosing “Draw” tab, one can expand the Sheet dropdown menu and choose Thicken Sheet. Now select the sheet, change the material to the substrate material.
Fig. 6. Thicken the equation based surface to generate the substrate
  • At this point you are ready to transfer the antenna design to the curved surface. Select both traces of the antenna and the curved substrate (as shown in Fig. 7). Then use Modeler->Surface->Project Sheet…, this will transfer the traces to the curved surface. Please note that the original substrate is still remaining. You need not delete it.
Fig. 7. Steps for transferring the design to the curved surface (a)

Fig. 7. Steps for transferring the design to the curved surface (b)

Fig. 7. Steps for transferring the design to the curved surface (c)
  • Next step is to generate the ground plane and move the wave port. In our example design we have a partial ground plane. For ground plane surface we use the same method to generate an equation based surface. Please keep in mind that the Z coordinate of this surface should be the same as substrate minus the thickness of the substrate. (If you thickened the substrate surface to both sides, this should be the height of substrate minus half of the substrate thickness). Once this sheet is generate assign a Perfect E or Finite Conductivity Boundary (by selecting the surface, right click and Assign Boundary). Delete the old planar ground plane.
Fig. 8. Non-planar meandered antenna with non-planar ground

Wave Port Placement using Equation Based Curve

A new wave port can be defined by the following steps:

  • Delete the old port.
  • Use Draw->Equation Based Curve. Mimicking the equation used for ground plane (Fig. 9).
Fig. 9. Use Equation Based Curve to start a new wave port (a) Equation Based Curve definition window (b) wave pot terminal created using equation based curve and sweep along vector
  • Select the line from the Model tree, select Draw->Sweep->Along Vector. Draw a vector in the direction of port height. Then by selecting the SweepAlongVector from Model tree and double clicking, the window allows you to set the correct size of port height and vector start point (Fig. 10).
  • Assign wave port to this new surface.
Fig. 10. Sweep along vector to create the new wave port location

Similar method can be used to generate (sin)^n or (cos)^n surfaces. Some examples are shown in Fig. 11. Fig. 11 (a) shows how the surface was defined.

Fig. 11. (a) Equation based surface definition using “cos” function, (b), (c), & (d) three different surfaces generated by this equation based surface.

Effect of Curvature on Antenna Matching

Bending a substrate can change the transmission line and antenna impedance. By using equation based port the change in transmission line impedance effect is removed. However, the overall radiation surface is also changed that will have effects on S11. The results of S11 for the planar design, cylindrical design (Fig. 8), cos (Fig. 11 b), and cos^3 (Fig. 11 c) designs are shown in Fig. 12. If it is of interest to include the change in the transmission line impedance, the port should be kept in a rectangular shape.

Fig. 12. Effect of curvature on the resonance frequency.

Equation based curves and surfaces can take a bit of time to get used to but with a little practice these methods can really open the door to some sophisticated geometry. It is also interesting to see how much the geometry can impact a simple antenna design, especially with today’s growing popularity in flex circuitry. Be sure to check out this related webinar  that touches on the impact of packaging antennas as well. If you would like more information on how these tools may be able to help you and your design, please let us know at info@padtinc.com.

You can also click here to download a copy of this example.

DesignCon 2017 Trends in Chip, Board, and System Design


Considered the “largest gathering of chip, board, and systems designers in the country,” with over 5,000 attendees this year and over 150 technical presentations and workshops, DesignCon exhibits state of the art trends in high-speed communications and semiconductor communities.

Here are the top 5 trends I noticed while attending DesignCon 2017:

1. Higher data rates and power efficiency.

This is of course a continuing trend and the most obvious. Still, I like to see this trend alive and well because I think this gets a bit trickier every year. Aiming towards 400 Gbps solutions, many vendors and papers were demonstrating 56 Gbps and 112 Gbps channels, with no less than 19 sessions with 56 Gbps or more in the title. While IC manufacturers continue to develop low-power chips, connector manufacturers are offering more vented housings as well as integrated sinks to address thermal challenges.

2. More conductor-based signaling.

PAM4 was everywhere on the exhibition floor and there were 11 sessions with PAM4 in the title. Shielded twinaxial cables was the predominant conductor-based technology such as Samtec’s Twinax Flyover and Molex’s BiPass.

A touted feature of twinax is the ability to route over components and free up PCB real estate (but there is still concern for enclosing the cabling). My DesignCon 2017 session, titled Replacing High-Speed Bottlenecks with PCB Superhighways, would also fall into this category. Instead of using twinax, I explored the idea of using rectangular waveguides (along with coax feeds), which you can read more about here. I also offered a modular concept that reflects similar routing and real estate advantages.

3. Less optical-based signaling.

Don’t get me wrong, optical-based signaling is still a strong solution for high-speed channels. Many of the twinax solutions are being designed to be compatible with fiber connections and, as Teledyne put it in their QPHY-56G-PAM4 option release at DesignCon, Optical Internetworking Forum (OIF) and IEEE are both rapidly standardizing PAM4-based interfaces. Still, the focus from the vendors was on lower cost conductor-based solutions. So, I think the question of when a full optical transition will be necessary still stands.
With that in mind, this trend is relative to what I saw only a couple years back. At DesignCon 2015, it looked as if the path forward was going to be fully embracing optical-based signaling. This year, I saw only one session on fiber and, as far as I could tell, none on photonic devices. That’s compared to DesignCon 2015 with at least 5 sessions on fiber and photonics, as well as a keynote session on silicon photonics from Intel Fellow Dr. Mario Paniccia.

4. More Physics-based Simulations.

As margins continue to shrink, the demand for accurate simulation grows. Dr. Zoltan Cendes, founder of Ansoft, shared the difficulties of electromagnetic simulation over the past 40+ years and how Ansoft (now ANSYS) has improved accuracy, simplified the simulation process, and significantly reduced simulation time. To my personal delight, he also had a rectangular waveguide in his presentation (and I think we were the only two). Dr. Cendes sees high-speed electrical design at a transition point, where engineers have been or will ultimately need to place physics-based simulations at the forefront of the design process, or as he put it, “turning signal integrity simulation inside out.” A closer look at Dr. Cendes’ keynote presentation can be found in DesignNews.

5. More Detailed IC Models.

This may or may not be a trend yet, but improving IC models (including improved data sheet details) was a popular topic among presenters and attendees alike; so if nothing else it was a trend of comradery. There were 12 sessions with IBIS-AMI in the title. In truth, I don’t typically attend these sessions, but since behavioral models (such as IBIS-AMI) impact everyone at DesignCon, this topic came up in several sessions that I did attend even though they weren’t focused on this topic. Perhaps with continued development of simulation solutions like ANSYS’ Chip-Package-System, Dr. Cende’s prediction will one day make a comprehensive physics-based design (to include IC models) a practical reality. Until then, I would like to share an interesting quote from George E. P. Box that was restated in one of the sessions: “Essentially all models are wrong, but some are useful.” I think this is good advice that I use for clarity in the moment and excitement for the future.

By the way, the visual notes shown above were created by Kelly Kingman from kingmanink.com on the spot during presentations. As an engineer, I was blown away by this. I have a tendency to obsess over details but she somehow captured all of the critical points on the fly with great graphics that clearly relay the message. Amazing!