PCB The layout engineer is constantly repeating the work of pulling wires with thousands of wires on the circuit board and various packages every day. Many people think that this is very boring and boring work. It seems to be just a simple software operation porter, but the designer has to choose between various design rules in the process, and needs to consider various aspects such as performance, cost and craftsmanship, and pay attention to the reasonable layout of the circuit board. Neat, not as simple as it seems, it contains a lot of work wisdom. Good working habits will make your circuit board design more reasonable, easier to produce, and better performance. Here are six good habits for designing circuit boards!

(1) Pay attention to details

Printed circuit board design is a meticulous job, all it takes is care and patience. Some mistakes often made by novices who are just starting to do circuit board design are detailed errors. For example, if the device pins are wrong, the device package is used incorrectly, the pin sequence is reversed, etc. Some can be solved by flying leads, but some may directly turn a board into a scrap. When drawing the package, check it more carefully, and compare the package with the actual device before projecting the board. Take a look and check it again is not OCD, but to avoid these low-level mistakes that are easy to make as much as possible. Otherwise, no matter how beautiful the design is, the board is covered with flying lines, and it will not be excellent.

(2) Setting rules

Now not only the advanced PCB design software needs to set the wiring rules, but also some simple PCB tools can also set the rules. After all, the human brain is not a machine, and it is inevitable that there will be negligence or mistakes. Therefore, set some easily overlooked problems into the rules, let the computer help us to check, and try to avoid making low-level mistakes. In addition, the perfect rule setting can better regulate the subsequent work. The so-called sharpening does not accidentally chop wood, the more complex the scale of the circuit board, the more important the rule setting becomes. Nowadays, many EDA tools have automatic routing function. If the rules are set in sufficient detail and the tools can help you design, wouldn’t it be pleasant for you to have coffee by the side?

(3) Consider more, work less

When designing a circuit board, consider the needs of the end user as much as possible. For example, if you are designing a development board, you must consider how to place more silk screen information when designing, so that it will be more convenient when you use it, and it will not be used to search for schematics or seek support from designers. If you are designing a mass production product, you must consider more about the problems that may be encountered on the production line. The same type of devices should have the same direction as possible, whether the device spacing is appropriate, the width of the circuit board process edge, and so on. The earlier these issues are considered, the less they will affect the subsequent design, and can also reduce the workload of subsequent support and the number of times to modify the circuit board. It seems that the time it takes to start the design has increased, but in fact it has reduced the amount of follow-up work. When the space signal of the circuit board allows, try to place more test points to improve the testability of the board, so that it can also save more time in the subsequent debugging stage and provide more ideas for finding problems.

(4) Draw the schematic diagram

Most engineers think that the layout work is more important. The schematic diagram is to generate a netlist to facilitate PCB inspection. In fact, the role of the schematic diagram will be greater in the subsequent circuit debugging process. Whether it is to find a problem or communicate with colleagues, the schematic diagram is more intuitive and convenient. In addition, develop the habit of labeling in the schematic diagram, and mark the issues that need to be paid attention to during the layout of each part of the circuit on the schematic diagram, which is a good reminder for yourself or for others. Hierarchical schematic diagrams divide the circuits of different functions and different modules into different pages, so that the subsequent workload can be significantly reduced both in terms of reading the diagram and in the process of repeated use in the future. Using a mature design is always less risky than designing a new circuit.

(5) Optimize circuit layout

After drawing the schematic diagram, the impatient engineer imports the netlist into the PCB and can’t wait to put the device in place and start pulling the wire. In fact, a good PCB layout can make your wire-drawing work easier and make the circuit board work better. Each board will have a signal path, and the circuit layout should follow this signal path as much as possible so that the signal can be transmitted smoothly on the board. People don't like to walk through the maze, and the signal is the same. If the schematic is designed in accordance with the module, the PCB is the same. According to different functional modules, the circuit board can be divided into several areas. Separate analog and digital, separate power supply signals, separate heating devices and susceptible devices, do not place larger devices too close to the edge of the board, pay attention to the shielding of radio frequency signals, etc.... Spend a little more time to optimize the PCB layout, you can Save more time when pulling the string.

(6) Try to do simulation

Simulation is often something that circuit board design engineers don’t want to touch. Some people may say that even if I simulate, the actual PCB produced will still be different from the simulation results, so why should I waste time doing simulation? Doesn't the board I made out of simulation work well? Right? This idea is very helpless. No problem with the design once or twice does not mean that there will be no problems in the future. Although the simulation results are different from the actual results, the simulation can show the correct trend of change, and we can make our own judgments based on the trend. There may be difficulties at the beginning, and it is normal for the simulation model to be confused about the simulation parameters. As long as you start to do and accumulate slowly, you will realize the importance of simulation. Before the completion of the circuit board, determine the location of the problem in advance, solve it in advance, and avoid the occurrence of the problem. If you do too much simulation, practice makes perfect, and you will quickly understand the root cause of the problem, which will greatly help you improve your design ability.

In actual work, if you can complete the above questions and develop a good working habit in your work, I believe that with the gradual improvement of personal ability, you will complete more Excellent design.

The above information comes from the public data collection on the Internet

Global high-end printed circuit brand——SINOSIGMA