The ten most effective design rules that electronic design engineers should keep in mind and practice when using design software for PCB layout design and commercial manufacturing.
Engineers do not need to implement these rules in chronological order or relative importance, just following them all can greatly change the product design.
Rule 1: Choose the right grid
Set and always use the grid spacing that can match the most components.
Although multiple grids seem to be effective, if engineers can think more at the beginning of PCB layout design, they can avoid difficulties in spacing setting and maximize the use of circuit boards.
Since many devices use multiple package sizes, engineers should use the products that are most conducive to their own designs.
In addition, polygons are crucial for circuit board copper plating. Multi-grid circuit boards generally produce polygon filling deviations when performing polygon copper plating. Although it is not as standard as based on a single grid, it can provide a circuit board life that exceeds the required life.
Rule 2: Keep the path shortest and most direct
This sounds simple and ordinary, but it should be kept in mind at every stage, even if it means changing the circuit board layout to optimize the wiring length.
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: Use power planes to manage the distribution of power and ground lines whenever possible
Power plane copper is the faster and simpler option for most PCB design software. By connecting a large number of wires in common, you can ensure that the current is provided with the highest efficiency and the minimum impedance or voltage drop, while providing an adequate ground return path.
If possible, you can also run multiple power lines in the same area of the board. Confirm that the ground plane covers most of the level of a layer of the PCB, which is conducive to the interaction between the lines running on adjacent layers.
For example, placing the discrete components required for OpAmp operational amplifiers close to the device so that bypass capacitors and resistors can work with it on the same ground, which helps optimize the wiring length mentioned in Rule 2 and also makes testing and fault detection easier.
Rule 5: Repeat the required board multiple times on another larger board for PCB assembly
Choosing the size that best suits the equipment used by the manufacturer can help reduce prototyping and manufacturing costs. Start by laying out the board on a panel, contact the board manufacturer to get their preferred size specifications for each panel, then modify your design specifications and try to repeat your design multiple times within these panel sizes.
Rule 6: Consolidate component values
As a designer, you will choose discrete components with higher or lower values but the same performance. By consolidating within a smaller standard value range, you can simplify the bill of materials and potentially reduce costs.
If you have a series of PCB products based on preferred device values, it will also help you make the right inventory management decisions in the long run.
Rule 7: Perform design rule checks (DRC) as much as possible
Although it only takes a short time to run the DRC function on the PCB software, in more complex design environments, as long as you always perform checks during the design process, you can save a lot of time and it is a good habit to maintain. Every routing decision is critical, and performing DRCs can remind you of the most important routing at any time.
Rule 8: Smart Use of Silkscreen
Silkscreen can be used to mark all kinds of useful information for future use by board manufacturers, test engineers, installers, or equipment commissioning personnel.
In addition to clearly marking functions and test point labels, mark the orientation of components and connectors whenever possible, even if these notes are printed on the underside of the components used on the board (after the board is assembled).
Make full use of silkscreen technology on both the upper and lower surfaces of the board to reduce duplication and streamline the production process.
Rule 9: Must-choose decoupling capacitors
Don't try to optimize your design by avoiding decoupling power lines and relying on the extreme values in the component data sheet.
Capacitors are inexpensive and durable, so you can spend as much time as possible assembling capacitors, while following Rule 6 and using standard value ranges to keep inventory neat.
Rule 10: Generate PCB manufacturing parameters and verify before submitting for production
While most board manufacturers are happy to download and verify directly for you, it is best to output the Gerber file yourself and check whether it is as expected with a free viewer to avoid misunderstandings.
By doing this yourself, you may even find some inadvertent mistakes and avoid costly production runs to the wrong parameters.
Conclusion
As circuit designs are shared more and more, and internal teams rely more and more on reference designs, basic rules like the above will continue to be a feature of printed circuit board design, and we believe it is very important for PCB design.
With these basic rules in mind, developers have great flexibility to increase the value of their products and get the most from the boards they manufacture. Even for novice board designers, keeping these basic rules in mind can speed up the learning process and increase confidence.
