PCBA Tech - Several golden rules of high-level PCB design

PCB is the physical platform for PCB design and the most flexible part of the original component electronic system design. Next, the PCB design company introduces to PCB design engineers the most effective design rules that should be remembered and practiced in PCB layout design and commercial manufacturing when using design software.

Since the birth of commercial PCB design 25 years ago, most of these principles have not changed. They are widely used in various PCB design projects, which have guiding significance for young PCB design engineers and more mature PCB manufacturers. Engineers do not have to follow these rules in chronological order or relative importance, but can drastically change product design by following them all.

High-level PCB design rule one

Choose the right grid-set and always use the grid spacing that matches most elements. Although multi-grid seems to be very effective, engineers consider the PCB layout as early as possible to avoid spacing difficulties and maximize the use of the circuit board. Since many devices are packaged in various sizes, engineers should use the product that best suits their design. In addition, the polygon is very important for the copper coating of the circuit board. Generally, polygonal filling deviations occur when polygonal coating is performed on a multi-gate circuit board. Although it is not like a standard based on a single grid, it can provide circuit board life beyond the requirements.

High-level PCB design rule 2

Keep the path shortest and most direct. It sounds simple, but it should be kept in mind even at each stage, even if it means changing the PCB layout to optimize the wiring length. This is especially true for analog and high-speed digital circuits, because in these systems, system performance is always partially limited by impedance and parasitic effects.

High-level PCB design rule three

Use the power plane to manage the distribution of power lines and ground lines as much as possible. For most PCB design software, power copper coating is a faster and easier choice. By sharing a large number of wires, it is possible to provide the most effective current with minimal impedance or voltage drop while providing sufficient ground loops. If possible, you can also lay multiple power lines in the same area of the circuit board to confirm whether the connection layer covers most of the PCB, which is conducive to the interaction between the lines on adjacent layers.

High-level PCB design rule four

Group related components with required test points. For example, the discrete components required by OpAmp operational amplifiers are placed close to the device so that bypass capacitors and resistors can work with them, which helps optimize the wiring length mentioned in Rule 2 and makes testing and fault detection easier .

High-level PCB design rule 5

Copy the required circuit board to another larger board several times to make the PCB. Choosing the best size for the equipment used by the manufacturer can help reduce prototyping and manufacturing costs. First lay out the circuit board on the panel, contact the circuit board manufacturer to obtain the preferred size specifications of each panel, then modify the design specifications, and try to repeat the design as much as possible within these panel sizes.

High-level PCB design rule 6

Integration component value. As a designer, you can choose high-value or low-value discrete components that are equally effective. Consolidating within a smaller standard value range can simplify the bill of materials and reduce costs. If you have a series of PCB products based on the value of your preferred device, it is best to make the right inventory management decisions in the long run.

High-level PCB design rule 7

Perform as many design rule checks (DRC) as possible. Although it only takes a short time to run DRC on the PCB, it is a good habit to maintain good habits in a more complex design environment where you can save a lot of time by checking throughout the design process. Every wiring decision is critical, and DRC can be used to remind you of the most important wiring decision.

High-level PCB design rules eight

Flexible use of screen printing. Screen printing can be used to mark various useful information for future use by circuit board manufacturers, service or test engineers, installers or equipment debuggers. Even if these precautions are printed on the lower surface of the components used on the circuit board (after the circuit board is installed), not only the function and test point labels are clearly marked, but also the direction of the components and connectors should be as clear as possible. Assembled on the upper and lower surface of the circuit board, making full use of screen printing can reduce repetitive work and simplify the production process.

High-level PCB design rule 9

Must choose decoupling capacitor. Don't try to optimize the design by avoiding decoupling power lines and following the limitations in the component data sheet. Capacitors are cheap and durable, so you can spend more time assembling them while following Rule 6 and using a series of standard values to keep inventory.

Ten principles of high-level PCB design

Generate PCB manufacturing parameters and verify them before submitting for production. Most circuit board manufacturers are happy to download and verify the file directly for you, but it is best to print out the Gerber file yourself and use a free reader to check whether the file meets expectations, so as not to cause misunderstandings. By checking yourself, you may even find some careless mistakes, so as to avoid losing the situation of following the wrong parameters.

With the widespread sharing of circuit designs and the increasing reliance of internal teams on reference designs, such basic rules will remain a function of PCB design, which we believe is very important for PCB design. With these basic rules, developers can flexibly increase the value of their products and make full use of their own circuit boards. Even for novice circuit board designers, as long as these basic rules are kept in mind, the learning process can be accelerated and confidence increased. Some companies need PCB engineers to master 1 or 2 PCB design tools.