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Effective Integrated Circuit Simulation Within Multi-board PCB Systems

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Once upon a time, watching a movie in a theater was a completely different experience than viewing the same movie at home. Obviously, the ambience was different, but the most significant variant was the screen size and visual perspective. At home, you were limited to approximately 30” or less, while theater screens were comparatively astronomical in size. This difference was not trivial, as it gave you a completely different and less complete perspective with which to base your interpretation of the film. Today, this discrepancy no longer exists and you can get the full effect of the film right in your home.

One of the most important things you can do before releasing your board design to the contract manufacturer (CM) is to analyze it. There are many reasons why this is important, not the least of which is to check connectivity and verify functionality. For simple components, checking trace connections is pretty straightforward. However, for integrated circuits, which tend to be more complicated, analysis is not as simple. And when your design includes many integrated circuits on multiple interconnected PCBs, the situation can be exasperating. 

Fortunately, there are means to aid you in performing this important system evaluation. The benefits of this type of support can best be appreciated by first looking at typical integrated circuit simulation on a single board and on multiple boards. Then we will look at the most effective way to perform integrated circuit simulation for single or multi-board PCB systems.  

Single-board Integrated Circuit Simulation

Integrated circuits, often referred to as IC chips, are the superstars of the world of electronics. More than likely, your board layout will include at least one and probably several of these devices. Their architecture can range from simple, for example, a group of identical discrete devices; such as NAND, NOR or XOR gates, to extremely complex with thousands of components and large numbers of internal circuits. 


PCB with multiple ICs

Simple and complex integrated circuits


Some of the more complex integrated circuits are field programmable gate arrays (FPGAs), microprocessing units (MPUs), which may range from a small number of pins to hundreds, and system on a chip (SoC) devices, that may contain an entire computer system on the integrated circuit. 

Although internal analysis of these devices cannot be done directly, integrated circuit simulation can be performed by supplying the required inputs and evaluating the device outputs. Augmenting your design methodology can elevate a mixed signal simulation process into a mixed level process. Using proper SPICE simulation, analog circuits can be designed using traditional design methodologies and digital circuits using a top down methodology. 

The results of this type of analysis can provide a wealth of important information that can be used to improve your board design. For example, you can verify device and board operation, check traces and measure signal integrity parameters, evaluate your boards thermal performance and setup controlled impedance and copper weights. 

Unfortunately, most PCB design packages do not provide the capability to perform integrated circuit simulation. In these cases, you will have to either recreate your design in another application or export it to a third party circuit analysis program. 

Integrated Circuit Simulation Across Multi-board Designs

PCBs usually do not function or operate in isolation. Instead, your board is far more likely to be required to send outputs to, receive inputs from and communicate with other boards as part of a multi-board PCB system. To accurately analyze your integrated circuits you must be able to evaluate the interconnections between boards as well as on the boards themselves. 

This level of simulation requires sophisticated system analysis software that can perform system level simulation as well as employ dedicated signal analysis, as board interconnections may be high density and high-speed. In virtually all cases, you will need to utilize a third-party program, such as the industry standard PSpice package


Design methodology flowchart from PSpice paper on VHDL and FPGA models


Utilizing creative design methodologies with SPICE simulators allows for both precise modeling of arrival times of input signals, and studying the behavior of analog circuits when controlled by an FPGA. 

The Most Effective Integrated Circuit Simulation

As discussed above, the ability to perform integrated circuit simulation provides many benefits. These are not limited to aiding in evaluating performance or operability. In fact, this simulation can help your design for manufacturing (DFM) by ensuring that layout specifications needed for desired functionality are in fact within the tolerances of your CM’s equipment and process capabilities prior to submission of your design package. However, incorporating an integrated circuit simulation regimen can add time and man-hours to your design process. Therefore, it is incumbent on you to seek the most efficient means of performing this simulation.

The most effective integrated circuit simulation process in one that allows you to simultaneously analyze your board or system and incorporate needed changes or modifications directly into your design without the back and forth between different software packages that typically is required. This can be accomplished with an advanced and integrated 3D design and 3D analysis environment, such as Cadence’s Allegro. 


Analyzing multiple PCBs with flex interconnects

Cadence 3D multi-board integrated circuit simulation capability 


As shown in the figure above, Cadence Allegro provides system level design and analysis that simplifies the evaluation and incorporation of design changes, thereby greatly reducing the time and cost associated with ensuring your design is ready for manufacture. 

For the most effective integrated circuit simulation for single or multi-board designs, Cadence provides powerful design and analysis tools to streamline your design process. PSpice Simulator, on top of providing the standards like 34,000 component model libraries and simulation on parameters, complete your circuits with vulnerability and tolerance analysis as well as other capabilities to ensure manufacturability of your design with minimal, if any, design changes. 

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts