Issue link: https://iconnect007.uberflip.com/i/1472851
22 DESIGN007 MAGAZINE I JULY 2022 All engineers and designers are probably familiar with SPICE; if you're not, you should be. I consider the ability to run a SPICE simu- lation a mandatory skill for any PCB designer. Advanced applications will go far beyond SPICE and should use some level of simulation to verify signal integrity, channel compliance, and EMI. 2D Simulators Not all PCB design applications include a 2D interconnect simulator that can return imped- ance, reflections, crosstalk, and return path tracking in a PCB layout. Applications that do include these simulators will not have it run- ning in the online DRC engine. For everyone else, there are both free and paid calculator applications that will give you a rough estimate of crosstalk and reflections. Within the standard workflow, 2D simulators can work as a verification tool for intercon- nects once layout and routing are completed. In most of these tools, the user interface is sub- optimal. ese are not point-and-click simula- tion tools that operate like DRCs. Some con- figuration is needed, and you need to know some inputs with high certainty to gain mean- ingful results. For this reason, these simulators are not oen accessed while the design is being created; you'll find that users wait until the design is near completion to use these if they are used at all. Electromagnetic Field Solvers Field solvers are great for back-end verifica- tion once a design is completed, or for demon- strating feasibility of a circuit/interconnect on the front end. In between, while you're actu- ally creating the design, they are practically absent. In any case, they are practically absent from the workflow for most designers. ere is another challenge here; users of these appli- cations need to be well-versed in methods for solving Maxwell's equations in all their various forms. at usually entails a graduate degree in engineering, physics, or mathematics. e results from these programs are very accurate, but only as long as all the input data for simulations are also accurate. ese pro- grams suffer from "garbage in, garbage out"; if the input data used in a field solver do not match reality, then the field solver results won't match reality either. ey also follow the same antiquated workflow you find in ECAD/ MCAD collaboration; you have to export the design from your ECAD soware, then import it into the field solver. So, what should simulation tools of the future look like? How can the CAD vendors and sim- ulation soware providers do better? Where PCB Simulation Tools Can Improve Clearly, there is a lot of room for improvement in terms of user experience and workflow inte- gration. Because the user experience for these tools can be difficult to manage for less-experi- enced designers, they get pushed to the begin- ning or the end of the design process; there is little simulation happening in the middle. It would be great to see a simulation toolset that is built into PCB design applications and that can be invoked like your DRC engine. Per- sonally, I would love to see something that is invoked like DRCs, but that is qualifying the design against a broader range of SI/PI/EMI metrics than just impedance, reflection, and crosstalk. Within the standard workflow, 2D simulators can work as a verification tool for interconnects once layout and routing are completed.