As an important link in hardware design, PCB layout is an absolutely important index that affects the reasonable performance of hardware circuit design. Many PCB layout engineers finish wiring according to the restrictions of hardware engineers or pease engineers, and these are often called “cable puller”. They repeated and mechanically finished a PCB layout. After a period of time, some of them may have some experience: which should be the same length, which should be thick, which should be parallel to ensure proper row spacing, and so on. However, they rely on so-called experience, and many of them know that they don’t know what it is. I think if we want to make a breakthrough, we must broaden our knowledge.
In other words, PCB layout engineers can’t let others think that they are “cable workers”. First of all, you must have a certain degree of circuit understanding (of course, the design ability of a hardware engineer is not necessary, and it is best if you can); Secondly, it is necessary for SI/PI engineers to perform pi/si analysis (of course, if possible, the ability to perform RF simulation is not required, which is the best).
With this knowledge, you can not only design a good PCB, but also get funds from hardware and SI/PI engineers, and even get advice on circuit design from PCB design.
Needless to say, some PCB designs summarize some principles:
1. About layout 1. Layout is a reasonable layout of circuit elements.
That kind of arrangement is reasonable. A simple principle is that the module division is very clear, that is, people can see which one is used to achieve what function by getting your PCB with a certain circuit foundation.
2. Specific design steps: First, according to the schematic diagram, form the initial PCB file, complete the pre-layout of PCB, determine the relative PCB layout area, and then tell the structure that the structure is based on the area given by us, and then give specific constraints according to the overall structure design.
3. According to the structural constraints, finish the drawing of the board edge, positioning opening and some forbidden areas, and then finish the placement of connectors. 4. Principle of component placement: Generally, the main control MCU is placed in the center of the circuit board, and then the interface circuit is placed close to the interface (such as mesh, USB, VGA, etc.), and most interfaces are ESD protected and filtered.
The next principle is to protect the post filter first.
5. Then the power supply module. Generally, the main power supply module is placed at the power supply entrance (such as system 5V), and the discrete power supply modules (such as module circuit power supply 2.5V) can be placed in a denser place in the same power grid according to the actual situation. 6. Some internal circuits are not introduced into the connector.
We generally follow such a basic principle: high-speed, low-speed division, analog, digital division, interference source, and sensitive receptor subregion.
7. Then for a single circuit module, follow the circuit design when designing the current. It is speculated that the whole circuit layout can join and correct the great God.
