As electronics design becomes more complex and design departments look for ways to handle the increased work-load, more PCB designers are stepping into multi-board system design. For those who have only worked with single board design in the past this could seem to be a little intimidating. I would guess though that you’ve already been through something like this before. Remember being back in school? You were working on multiple projects every day. Some math here and a little history there, you were a champion of multi-project work without even realizing it. And on those days that it seemed more appealing to hang out with your friends instead of working on your projects, you also got to experience full system failure for the first time too.
But in all seriousness, there are some similarities to your time in school that may be helpful to remember. In school you would block out time for each subject, organize your work, and then methodically work on each project equally making sure that they all were completed on time. For multi-board system design you will also block out the system into separate boards, and then make sure that each board is supported equally so that the entire system is designed together. Let’s take a closer look at designing multi-board enclosures in full system design.
System Schematic Design of Multi-Board Enclosures
Full system design starts in PCB CAD tools that are set up for multi-board design. Like a map, full system design starts with the top level architecture of the system represented on a schematic. This schematic map will have blocks representing the individual system boards as well as the connectivity between each of those boards. You have the ability to place your blocks, add text, and connect the blocks together. What is unique about this map though is that each block is linked to its own individual board level schematic.
Each board schematic represented on the system level schematic will function as a regular schematic once you are working in it. You will place symbols, connect nets, and run regular DRCs. Each schematic will also be linked to its own layout, just as you are used to working with now. The difference will be that all of the individual system board designs are connected together at the system level. All of the connectivity that you draw at the system level will connect each board together. In the past this type of system design used to be handled by secondary spreadsheet or presentation tools that had no intelligent connectivity connection to the individual PCB designs that it represented. With system level design in your PCB design tools, you now have the power to design your system together.
Full system design can help you design and see all the boards together
Individual Board Layout within Multi-Board Design
When it comes time to work on the layout, that too will be the same as you are used to when working on a single PCB design. You will create the board outline and define the layer stackup, then you will place the parts and route the traces just as you always have. What is different is how you can assign the work-load of the designs and work together with the other board layouts in the system.
With system level design you can assign work-loads to different team members. This collaborative system of design is usually regulated by team assignment features within the multi-board system tools. These features allow for the management of work by creating specific areas for each team member to work in. Another feature of system design is the ability to combine each system level board into a single 3D environment. This allows for verification of size and fit of each board to each other and within the system enclosure. This gives engineers the power of real-time assembly virtual prototyping all from the CAD tools on their desktop.
Full system PCB design tools can unfold a group of boards from their enclosure
System Simulation and the Tools to Take You There
Another major benefit of full system PCB design tools is the ability to simulate not just the individual PCB designs, but to simulate all the designs together at the system level. For example, high speed and power signals within a multi-board system should be simulated to check for any issues so that engineers can tune the signals across the entire system to ensure the best performance.
They can plan out the most optimum power delivery network for the entire system too. This level of system simulation as well as the virtual 3D prototyping of all of the system boards together within the enclosure will give engineers a level of design capabilities that they’ve not had before. These tools will help to reduce design time and cost, as well as decrease the need for production prototypes while improving manufacturing yields.
The key to all of this is to have the right PCB design tools in place for full system design. Allegro PCB Designer from Cadence is part of their multi-board PCB design system. This system gives you the features and functionality that we’ve been talking about here so that you can get ahead of the curve on your multi-board system designs.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.