Designing with Multiple PCBs

Many products include multiple, interconnected printed circuit boards. Bringing these boards together inside the enclosure and ensuring they correctly connect to each other is a challenging phase of the product development process. Have the nets been assigned correctly on each connector? Are the connectors oriented correctly? Do the plug-in boards fit together? Do all of the connected boards fit into the enclosure? A mistake at this late stage of the product development cycle is costly, both for the cost of redesign and the delay to market.

Managing this requires a design environment that supports system-level design. Ideally this will be a design space where you can define both the functional, or logical system, as well as a space where you can plug together the various boards and verify that they connect correctly, both logically and physically.

Altium Designer brings system-level design to the electronic product development process.

Capturing the Logical System Design

The overall system design is created in Altium Designer as a multi-board project. Within that project, the logical system design is drawn up by placing Modules on a multi-board schematic, where each physical board in the system is represented by a Module. Each Module references the PCB project and the board within that project. 

Once the Modules have been connected to each other on the multi-board schematic, the board-to-board connectivity can be verified. This will detect net-to-pin assignment errors and pin-to-pin interconnection wiring errors. These errors can be resolved and corrections pushed down into the affected PCB projects, or bought back up to the source system schematic.

► Read about Capturing the Logical System Design

Creating the Physical Board Assembly

A printed circuit board does not exist in isolation, instead they are often assembled together with other boards, and that assembly of boards is housed inside a case or enclosure. Helping to move through this stage of the design process, the software supports creating a multiple-board assembly, referred to as a Multi-board assembly.

The Multi-board Assembly editor allows exporting the entire multi-board assembly in either STEP or Parasolid format. It also allows other parts, including other boards and assemblies to be imported and positioned in the assembly.

Mates can be defined to form a connection formed between two separate objects. The connection is at a user-selected point on a surface on each object. Once mated the objects will re-orient so their surface planes and their perpendicular axes are aligned.

Assembly boards can be created as rigid-flex designs. Rigid-flex is the name given to a printed circuit that is a combination of both flexible circuit(s) and rigid circuit(s). Altium Designer's rigid-flex support enables you to view the board in the final folded state. Read more about rigid-flex designs here.

► Read about Creating the Physical Multi-board Assembly

Generating Multi-board Production Data

When it comes to the production of a Multi-board product design, additional information is required that represents a collated version of the projects within the system level design. How the sub modules are physically arranged and connected together, what component parts are needed for the complete design and who supplies them are all crucial factors for the successful production of a Multi-board design.

Altium Designer supports this system level approach to the design production through the application of its advanced ActiveBOM feature, assembly file generation and Output Job configurations. When added to the Assembly and Fabrication data produced by the individual sub projects, the production-based data included in the upper Multi-board project ensures that all component information, reports and files represent the complete product design.

► Read about Generating Multi-board Production Data