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The Sequence of PCB Design Services

Key Takeaways

  • PCB design services begin with the design of electronic system architecture and end with the development of a functional prototype.

  • A PCB schematic is the plan or blueprint required in PCB designing.

  • In the PCB layout design stage, the designer completes routing and component placement. 

 PCB board

I once worked on a power electronics project where the controller board was vertically connected to the power circuit. The circuit board was not giving the required output even when the controller PCB was working right. After debugging, our team concluded that there were some routing errors in the power board. The PCB design services received from the service bureau to whom we had outsourced the work turned out to be terrible. We had to rework the circuit board, which was challenging and delayed the project. As a precaution, we blacklisted that particular service bureau from further projects. As we learned, a bad PCB design service can negatively impact a project in many ways, as each phase of PCB design is critical to a product’s success. 

The Sequence of PCB Design Services 

PCB design services play a significant role in meeting the quality, reliability, and accuracy demands of the electronics market. There is a specific sequence followed in any PCB design process: PCB design services begin with the design of electronic system architecture and end with the development of a functional prototype. Let’s take a closer look at what happens during the design, layout, fabrication, assembly, and testing phases of PCB design.

Design Stage

PCB layout design is the first step of a PCB design service if design schematics are provided. If not, the work starts by drawing the PCB design schematic. Design schematics are the circuit diagrams that represent the electrical connections between the components used in a circuit. Any CAD software can be used to draw design schematics. With an error-free,  clutterless design schematic, the layout design becomes simpler.

Design schematics are the pictorial representation of the circuit that will be fabricated. Using the standard symbols, the PCB design schematic describes the electrical connections, components to be used in the circuit, and how they are interconnected. In a PCB schematic, you may find components and wires. The wires in the PCB schematic are replaced by traces in the PCB layout. A PCB design schematic is not concerned with component placement—that part becomes relevant when designing the PCB layout.

PCB schematics may be developed from specifications, block diagrams, marked-up schematic sheets, or simply from verbal discussions. Regardless of the source, CAD software is essential for creating PCB schematics.

Layout Stage

With the help of PCB design software, design schematics can be converted into a bill of materials and PCB layout. PCB layout design must be done carefully to avoid noise effects, signal degradation or loss, interference issues, thermal stresses, and mechanical stresses. PCB layout design includes the component placement and routing of the board. In PCB layout design, routing establishes the electrical connections between the components in the circuits through traces.

PCB design software is essential for converting a PCB schematic into a PCB layout. The PCB schematic imported to the PCB design software forms a layout design with component footprint and ratlines. Ratlines are automatically drawn between the pads belonging to the same net name. Ratlines reveal how different components can be connected with a track and help the designer route traces as well as create vias and copper pours on the board.

In the PCB layout stage, the designer completes routing and component placement. Various design considerations are involved in the PCB layout design such as the number of layers, PCB stackup structure, component dimension selection suitable for the size of the enclosure, board edge spacing, trace width, and hole spacing. The designer should stick to the PCB rules appropriate for the circuit under design to establish signal integrity, power integrity, interference mitigation, thermal stability, and mechanical stability.

Once the PCB layout is ready, texts or designators such as the board name, company name, version number, pin markings, switch settings, assembly instructions, copyright, and legal information can be marked on the board. These silkscreen texts make PCB assembling, reworking, and debugging easier. The file containing the completed PCB layout is then transferred to the PCB manufacturer for production. 

Fabrication, Assembly, and Testing Stages

A good PCB layout needs to satisfy requirements such as signal integrity, power integrity, and electromagnetic compatibility (EMC). Simulations can be run on the PCB layout to confirm the layout satisfies these requirements and evaluate board-level limitations. An approved PCB design layout is the manufacturer’s reference for PCB fabrication, and the layout can be exported in the format required by the manufacturers. In certain cases, a 3D model of the PCB is created to either design the enclosure or ensure the assembled PCB will fit inside the enclosure. After PCB fabrication and component assembly, the board is tested to ensure its proper functioning.

With the right design software, PCB design service companies can develop quality products. Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you’re looking to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.