The first of the major PCB design steps is a need. For most electronic engineers, these requirements are dictated by the customer, who will list all the requirements the PCB must meet. The electronic engineer must then convert the needs listed by the client into electronic form. Essentially, this means translating them into a language of electronic logic, which is what the engineer will use when designing the PCB.
The needs of the project determine several aspects of the design of the PCB. This includes everything from the materials to the final appearance of the PCB itself. The application of the PCB, such as medical or automotive, will often determine the materials in the PCB. For example, many medical PCBs for electronic implants are made with flexible bases. This allows them to fit in small spaces while also withstanding an internal organic environment. The final appearance of the PCB is determined mostly by its circuits and functionality – for instance, many more complex PCBs are made with multiple layers.
The electronic engineer will determine and list these needs, then use this list of requirements to design the initial schematic of the PCB, as well as the BOM.
The schematic design is essentially the blueprint manufacturers and other engineers use during the development and production processes. The schematic determines the function of the PCB, the characteristics of the design and the placement of components. The hardware of the PCB is also listed in this schematic. This equipment includes the material of the PCB, the components involved in the design and any other materials the manufacturer will need during the production process.
All this information is contained in the schematic during the initial design stage. After finishing the first schematic, the designer does a preliminary analysis, checking for potential problems and editing them as necessary. The schematic is then uploaded to a special tool for use in PCB design software, which can run simulations to ensure functionality. These simulations enable engineers to catch any design errors they may have missed during initial schematic check. After that, the electronic design of the circuit can be converted into a “netlist,” which lists information about the interconnectivity of components.
While considering the design of their schematic, electronic engineers should keep in mind a few crucial circuit board design basics from the start. A few of these considerations to implement during the schematic development stage include the following:
- • Selecting Appropriate PCB Panel Size: Selecting the board size most compatible with the equipment to be used is a basic, yet often forgotten, best practice. This way, extra space isn’t wasted, traces are kept to a minimum length, and overall material costs are kept somewhat low. It is important, however, to ensure that the design specs are optimized for mass production. Going too small with a board design may not be feasible for mass-production setups that produce enough variation between pieces to disrupt smaller designs.
- • Select the Correct Grid: Grid spacing is always set and applied to suit most components. Sticking to this grid is one of the most beneficial things an engineer can do to avoid spacing issues, so selecting the best one for the job is crucial. If some parts don’t work as well with the grid, the designer should try to find alternatives, or, better yet, use self-designed products.
- • Implement DRC as Much as Possible: Many PCB assembly companies make the mistake of running design rule checks (DRC) software only at the end of the design process. This lets small mistakes and questionable design choices build up, resulting in more remedial work at the end of the design process. Instead, designers should check their work with a DRC as often as is workable. This allows them to address problems identified by the DRC as quickly as possible and minimizes the number of massive changes at the end of the design process. This ends up saving time and smoothing out the editing process, so it isn’t as back-heavy.