Integrated circuits are indispensable in PCB design. Integrated circuits also have many, many small skills that can be used. The following skills are hoped to be helpful to everyone. Adding a decoupling capacitor can effectively remove the effects of burrs on the power supply and reduce the radiation of the power loop on the printed board, and reduce the instantaneous overshoot of the voltage on the power supply of the integrated circuit chip. When the decoupling capacitor is directly connected to the power supply leg of the integrated circuit instead of the power supply layer, the effect of smoothing the burr is best. This is why some device sockets have decoupling capacitors, and some devices require the distance between the decoupling capacitor and the device to be small enough. Any high-speed and high-power devices should be placed together as much as possible to reduce the transient overshoot of the power supply voltage. If there is no power layer, the long power connection will form a loop between the signal and the loop, becoming a radiation source and a sensitive circuit. The situation where the traces form a loop that does not cross the same network cable or other traces is called an open loop. If the loop passes through other wires of the same network cable, it constitutes a closed loop. In both cases, antenna effects (wire antennas and loop antennas) are formed. The antenna generates EMI radiation externally and is also a sensitive circuit itself. The closed loop is a problem that must be considered because the radiation it generates is approximately proportional to the area of closed loop. Written at the end: High-speed circuit design is a very complicated process. Some common methods described in this article may not be able to solve everyone's problems. There are many other factors that need to be considered when designing a circuit. These factors Sometimes opposing each other. Sometimes they affect each other, so we need to weigh various factors in the design, make the most comprehensive consideration, and design a comprehensive plan that not only meets the requirements but also reduces the design complexity.