Despite the increasing integration of semiconductors, many applications have ready-to-use system-on-a-chip, and many powerful and out-of-the-box development boards are becoming more readily available, but the use of electronics in many use cases Still need to use a custom PCB. In a one-time development, even a common PCB can play a very important role. PCB is the physical platform for design and the most flexible component for the original components for electronic system design.
The following sections describe the most effective design rules that electronic design engineers should keep in mind when implementing design layout and commercial manufacturing using design software.
Rule 1: Select the correct grid, set and always use the grid spacing that matches the most components. Although multi-grid seems to have significant utility, if engineers can avoid problems when setting up the interval and maximize the application of the board if they can think more at the beginning of the PCB layout design. Since many devices are available in a variety of package sizes, engineers should use products that are best suited for their design. In addition, polygons are critical for board copper deposition. Multi-grid boards typically produce polygon fill deviations when performing copper-clad copper. Although not as standard as a single grid, they provide the required board life.
Rule 2: Keep the path the shortest and most direct. This sounds simple, but at every stage, even if you want to change the board layout to optimize the wiring length, you should always keep in mind. This is especially true for analog and high-speed digital circuits where system performance is always partially limited by impedance and parasitic effects.
Rule 3: Manage the distribution of power and ground lines as much as possible using the power plane.
Rule 4: Group the relevant components together with the required test points. For example, placing the discrete components required for an Opamp op amp close to the device so that the bypass resistance and capacitance can cooperate with it, helping to optimize the wiring lengths mentioned in Rule 2, while also making test and fault detection It’s easier.
Rule 5: Repeat the copying of the required board on another larger board multiple times for PCB splicing. Choosing the size that best suits the equipment used by the manufacturer helps to reduce prototyping and manufacturing costs. First make the board layout on the panel, contact the board manufacturer to get the preferred size specifications for each of their panels, then modify your design specifications and try to repeat your design multiple times within these panel sizes.
Rule 6: Integrate component values. As a designer, you will choose some discrete components with high or low component values but the same performance. By integrating within a small range of standard values, bills of materials can be simplified and costs can be reduced. If you have a range of PCB products based on your preferred device values, from a long-term perspective,it will be better for you to make the right inventory management decisions.
Rule 7: Perform as many design rule checks as possible (DRC). Although it takes only a short time to run the DRC function on the PCB software, in a more complex design environment, as long as you perform the check during the design process, you can save a lot of time. This is a good habit to keep. Every cabling decision is critical, and you can always remind you of the most important cabling by performing a DRC.
Rule 8: Flexible use of screen printing. Screen printing can be used to label a variety of useful information for future use by board manufacturers, service or test engineers, installers, or equipment commissioners. Not only should the clear function and test point label be marked, but the direction of the components and connectors should be indicated as much as possible, even if these annotations are printed on the lower surface of the components used in the circuit board (after assembly of the circuit board). Full application of screen printing technology on the upper and lower surfaces of the PCB reduces duplication of effort and streamlines the production process.
Rule 9: Decoupling capacitors must be selected. Do not attempt to optimize your design by avoiding decoupled power wire and depending on the limits in the component data sheet. Capacitors are inexpensive and rugged, so you can spend as much time as possible assembling the capacitors, while following Rule 6, using standard values to keep stocks tidy.
Rule 10: Generate PCB manufacturing parameters and verify them before submitting for production.
As circuit design is becoming more widely shared and internal teams are increasingly relying on reference designs, basic rules like the above will remain a feature of printed circuit board design, which we believe is important for PCB design. By clarifying these basic rules, developers have the flexibility to increase the value of their products and get the most out of the boards they manufacture.