1. Bare board size & shape
The first thing to consider in PCB layout design is the size, shape and number of layers of the bare board. The size of the bare board is often determined by the size of the final electronic product, and the size of the area determines whether all the required electronic components can be placed. If you don’t have enough space, you might consider a multi-layer or HDI design. Therefore, it is critical to estimate the board size before starting the design. The second is the shape of the PCB. In most cases, they are rectangular, but there are also some products that require the use of irregularly shaped PCBs, which also have a great impact on component placement. The last is the number of layers of the PCB. On the one hand, multi-layer PCB allows us to carry out more complex designs and bring more functions, but adding an extra layer will increase the production cost, so it must be determined in the early stage of design. specific layers.
2. Manufacturing process
The manufacturing process used to produce the PCB is another important consideration. Different manufacturing methods bring different design constraints, including PCB assembly methods, which must also be considered. Different assembly technologies like SMT and THT will require you to design your PCB differently. The key is to confirm with the manufacturer that they are capable of producing the PCBs you need and that they have the skills and expertise needed to implement your design.
3. Materials and components
During the design process, the materials used and whether the components are still available in the market need to be considered. Some parts are hard to find, time consuming and expensive. It is recommended to use some of the more commonly used parts for replacement. Therefore, a PCB designer must have extensive experience and knowledge of the entire PCB assembly industry. Xiaobei has professional PCB design Our expertise to select the most suitable materials and components for customers’ projects, and provide the most reliable PCB design within the customer’s budget.
4. Component placement
PCB design must consider the order in which components are placed. Properly organizing component locations can reduce the number of assembly steps required, increasing efficiency and reducing costs. Our recommended placement order is connectors, power circuits, high-speed circuits, critical circuits, and finally the remaining components. Also, we should be aware that excessive heat dissipation from the PCB can degrade performance. When designing a PCB layout, consider which components will dissipate the most heat, keep critical components away from high-heat components, and then consider adding heat sinks and cooling fans to reduce component temperatures. If there are multiple heating elements, these elements need to be distributed in different locations and cannot be concentrated in one location. On the other hand, the direction in which components are placed also needs to be considered. Generally, similar components are recommended to be placed in the same direction, which is beneficial to improve welding efficiency and reduce errors. It should be noted that the part should not be placed on the solder side of the PCB, but should be placed behind the plated through hole part.
5. Power and ground planes
Power and ground planes should always be kept inside the board, and should be centered and symmetrical, which is the basic guideline for PCB layout design. Because this design can prevent the board from bending and causing the components to deviate from their original position. Reasonable arrangement of power ground and control ground can reduce the interference of high voltage on the circuit. We need to separate the ground planes of each power stage as much as possible, and if unavoidable, at least make sure they are at the end of the power path.
6. Signal Integrity and RF Issues
The quality of PCB layout design also determines the signal integrity of the circuit board, whether it will be subject to electromagnetic interference and other issues. To avoid signal problems, the design should avoid traces running parallel to each other, because parallel traces will create more crosstalk and cause various problems. And if the traces need to cross each other, they should cross at right angles, which can reduce the capacitance and mutual inductance between the lines. Also, if components with high electromagnetic generation are not required, it is recommended to use semiconductor components that generate low electromagnetic emissions, which also contributes to signal integrity.
Post time: Mar-23-2023