Digital ground cables should be separated from analog ground cables. This has a certain degree of difficulty in practice. To develop a better board, you first have to understand the electrical aspects of the IC you are using, which pins will produce high order harmonics (digital signals or the rise/fall edge of the switching square wave signal), which pins are susceptible to electromagnetic interference, the signal block diagram (signal processing unit block diagram) inside the IC helps us understand.

The layout of the whole machine is the first condition to determine the electrical performance, and the layout of the board is more to consider the direction or process of the signal/data between the IC, the big principle is easy to produce electromagnetic radiation as close to the power part as possible; The weak signal processing part is mostly determined by the overall structure of the equipment (that is, the overall planning of the early equipment), and the weak signal processing part is as close as possible to the input or detection head (probe) of the signal, which can better improve the signal-to-noise ratio and provide more pure signal/accurate data for subsequent signal processing and data recognition.