In PCB design, the ground line is usually divided into protection ground and signal ground; the power ground is divided into digital ground and analog ground. Why should the ground line be divided?
The purpose of dividing the ground is mainly due to EMC considerations, and it is worried that the noise of the digital part of the power supply and the ground will interfere with other signals, especially the analog signal through the conduction path. As for the division of the signal and the protection ground, it is because of the static discharge of ESD in EMC, similar to the role of lightning rod grounding in our lives. No matter how it is divided, there is only one final land. It’s just that the noise is different.
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