Multi-Circuit Board Design Rules: Designing PCBs for Interconnected Systems in Altium Designer

Zachariah Peterson
|  Created: October 5, 2020
The Necessity of Multi-Board System-Level Design

If you open up some of your favorite electronics, you’ll find they are multi-circuit boards systems or multiple PCBs connected together with cables and ribbons. In the past, circuit design software has treated each board in the system individually without considering important circuit board design issues like power distribution and grounding, high-speed routing, mechanical assembly, and thermal demands.

Design software has caught up to the demands of professional circuit board designers, but how do you choose the PCB design package you need to create your next multi-board system design? The answer lies in considering all the available functions and features in your PCB design software.

When you use Altium Designer, you’ll have access to a full suite of design tools that are naturally adapted to multi-PCB design. Your circuit board design tools will integrate with your multi-board system design features in a single program.


The most powerful, modern, and easy-to-use PCB design tool for professional use.

For years the standard system design workflow has been to develop the individual PCB design, and then physically fit its prototype build into the full system mockup. With today’s complex designs offset by demands for reduced design schedules and budgets, the old workflow has become a logjam due to the time and expense of continual prototyping. Successful system design still requires working with all the boards together in order to verify their fit and connectivity. However, the question is, how can this be accomplished in a more timely and productive fashion?

In the old days, you’d have to manually track connections between printed circuits boards in a multi-board system design with MCAD tools or by hand. Now, ECAD software can link the layout and schematic for each circuit board and apply design rules to each section. With the right design software, your standard routing and rules checking tools will be spread across each PCB in a multi-board system. This is how Altium Designer makes multi-PCB design easy and helps you build advanced electronics.

The Necessity of Multi-Board System-Level Design

Historically, PCB design has been handled on a board-by-board basis. The traditional design flow may have included a high-level multi-circuit boards design, but the actual boards were designed individually. Not only was this the standard practice, but the older design systems didn’t have the capabilities for multi-board design, to begin with. Once the PCB designs prototypes were built, then the boards would be tested for form, fit, and function with the other system boards. Corrections would then be made in the next revision of circuit board designs to get the boards to work correctly together.

This approach no longer works for the advanced technologies that are being created today. The requirement for more system-level design is increasing while the need to shorten design cycles is increasing as well. To keep up with these requirements, the traditional methods of system-level PCB design need to be updated with CAD tools that can handle the complexities of multi-board system-level design.

Nets and trace highlighted in 3D layout for Altium Designer

The right multi-board PCB design features help you quickly identify nets in your 3D PCB layout.

Getting Started with Multi-Board PCB Design

Multi-board PCB design follows the same process and designing a single circuit board. Components are added to schematics for each board, and the schematics are captured as an initial layout. Plane layers, vias for layer transitions, pads, and copper traces are all designed for each board in the system. The magic in multi-PCB design comes from defining electrical connections between each board, and in designing the arrangement of the various circuit boards in 3D.

Moving Through Multi-board System Design with the Right Software

You’ll need the following tools for effective multi-board system-level design and PCB layout:

  • Schematic capture tools, including hierarchical schematic capture to define circuits for different boards
  • Layer stack manager for each board with via links between layers
  • PCB layout and routing features that operate in 2D and 3D
  • Access to component libraries and footprints for board-to-board connectors and pin headers
  • MCAD tools to define the circuit board arrangement

The multi-PCB design process begins with schematic capture, transitions to a complete printed circuit board layout for each board, and ends with a complete documentation package that describes all aspects of your multi-board system. Along the way, your circuit board design software will need to integrate data from a number of sources, including your components, layer stack, and all other aspects of your circuit board.

Once it comes time to plan your multi-board system design for production, you will need features that allow you to generate consistent documentation and assembly instructions for any manufacturer directly from your design data. Printed circuit design and manufacturing can finally be addressed in a single program when these important tasks are integrated into a single program with a consistent interface.

Screenshot of multi-board design in Altium Designer

Once each circuit board in the system is designed and the PCB layout is created, you can arrange your boards in 3D with MCAD features.

Multi-board PCB Design Needs MCAD Integration

Any multi-board PCB design requires mechanical verification to ensure each circuit board will fit together properly. Boards that connect with pin headers or other connectors need to satisfy tight mechanical constraints in order to prevent collisions between components. The best way to do this is with MCAD features, which allow you to view each circuit board in 3D, as well as your system of boards.

Unfortunately, most low-quality printed circuit board design platforms do not include these features alongside your standard printed circuit design features. You’ll be forced to export your design to a mechanical design program, where you’ll lose the ability to co-design your printed circuit features. This is why you need to use a design application that integrates all these important features into a single application.

Why Multi-PCB Design Needs Integrated ECAD/MCAD Design

When your ECAD features are integrated into a single platform alongside MCAD features, you won’t need to switch between programs to complete important mechanical design tasks. All your design rules will be checked and handled in 3D as you prepare your mechanical design. This lets your produce the most accurate 2D and 3D layouts in a single program and prepares them for the manufacturing process.

Screenshot of section view in Altium Designer’s unified design environment

Multi-board design works best when your ECAD software contains MCAD tools. You’ll have the power to quickly cut into different board sections and verify mechanical constraints.

Multi-board PCB Design, Layout, and Manufacturing in a Single Platform

Multi-board PCB design can be a difficult task that requires the best circuit design software, simulation, verification, and documentation tools on the market. While other printed circuit board design platforms split these tools into different programs, you’ll only find all these features in one application when you use Altium Designer. This unique printed circuit board design platform offers a modern workflow that helps you complete the most advanced design tasks in a single program.

The 2D and 3D CAD tools in Altium Designer allow you to fully verify the accuracy of your system-level design and multi-board PCB design before you send your board out for production. The unified design environment gives you access to every design feature you need without switching between multiple programs. In addition, you’ll be able to generate every manufacturer deliverable you can imagine, and all within a single design platform.

Altium Designer Makes Multi-PCB Design Easy

The multi-circuit boards PCB design functionality in Altium Designer uses a 64-bit multi-threading architecture, giving Altium Designer the power to handle any challenge. While the simple, intuitive interface in the schematic editor lends itself to first-time users, it is also one of the most powerful and versatile schematic capture applications available today. It has been created to handle the most complex hierarchical and multi-channel designs. Multi-board PCB design capabilities are built into Altium Designer, and you can even import your design into popular MCAD applications for enclosure design and modeling.

The capability to support the transition from ECAD to MCAD within Altium Designer serves as a major factor for multi-board designs. Because MCAD systems do not consider electrical rules, the interaction between ECAD and MCAD allows the placement of densely packed components with collision checks. The Multi-board Assembly Editor also shows how the PCBs plug into one another. Altium Designer exports 3D STEP files and the correct Step enclosure data to ensure that boards do not exceed specified height profiles.

multi-board PCB design

Easily construct, view, and manipulate your multi-board assembly in Altium Designer

With Altium Designer, the only thing you need to worry about is designing top-quality electronics. With Altium Designer’s multi-PCB design technology, you’ll have full control over all aspects of your multi-board PCB design process, and you can verify your system-level design before you send your circuit boards out for manufacturing. It’s time to take control over your multi-board PCB design: it’s time to try Altium Designer.

Altium Designer on Altium 365 delivers an unprecedented amount of integration to the electronics industry until now relegated to the world of software development, allowing designers to work from home and reach unprecedented levels of efficiency.

We have only scratched the surface of what is possible to do with Altium Designer on Altium 365. You can check the product page for a more in-depth feature description or one of the On-Demand Webinars.

About Author

About Author

Zachariah Peterson has an extensive technical background in academia and industry. He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics. His work has been published in over a dozen peer-reviewed journals and conference proceedings, and he has written 2500+ technical articles on PCB design for a number of companies. He is a member of IEEE Photonics Society, IEEE Electronics Packaging Society, American Physical Society, and the Printed Circuit Engineering Association (PCEA). He previously served as a voting member on the INCITS Quantum Computing Technical Advisory Committee working on technical standards for quantum electronics, and he currently serves on the IEEE P3186 Working Group focused on Port Interface Representing Photonic Signals Using SPICE-class Circuit Simulators.

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