As a PCB Assembly Manufacturer, share with you.

When we draw the board, we often hear a sentence that is to make the loop as small as possible. Now let's look at a simple explanation.

PCB wiring diagram, using electromagnetic field knowledge can know, then this board becomes a good antenna, and the circuit board design becomes a mess. The electromagnetic interference generated by the wiring is much smaller, which is the idea of minimizing the magnetic flux of the circuit board.

It is a good choice to use the mirror plane when designing, it can effectively eliminate the interference caused by the power or ground plane to the electronic circuit. Mirror plane refers to the plane that constitutes the return flow, such as the power and ground planes at most levels, but there are also mirror planes where the power and power planes, such as RS232 level, etc. The image plane can also be regarded as a differential signal, and the differential signal has a good suppression effect on common mode interference, and the distance between the image plane should be as small as possible. If it is a double-sided board or a single-sided board, it is a good method to pave copper on both sides and punch more holes. Generally do not stack two unrelated power supply planes together, especially when the voltage difference is relatively large, otherwise the mutual interference of power supplies will become serious due to the effect of capacitive coupling. No matter how well the PCB layout is designed, the magnetic field and electric field will always exist. However, if the magnetic flux is reduced or eliminated, the EMI becomes very small or non-existent.

When designing the PCB board, through good wiring to reduce the board signal line loop (reduce the magnetic flux generated by the signal line) to reduce interference, I have summarized the following methods:

1. The design of the multilayer board is based on the multilayer board stacking setting and the signal line impedance control. For the top layer, power supply, ground and bottom layer of the 4-layer board, on the one hand, this greatly solves the problem of electromagnetic interference and improves the reliability of the system.

2. On the other hand, it can increase the wire distribution rate and reduce the area of the PCB board. The 6-layer board usually adds 2 signal layers to the 4-layer board. An 8-layer board usually includes a power layer, two ground layers, and 5 signal layers. For the layer setting, there are abundant information on the Internet, or leave a message to discuss. Our company also has PCB Bare Board on sale, welcome to contact us.