How should the power ground and signal ground of the concentrator be separated?

If power ground (which carries a large current from the switching power supply) and signal ground (for acquisition and communication) are mixed in a concentrator, power ground noise will severely pollute the signal ground. Proper splitting and single-point connection are crucial. On the PCB, separate the power ground area from the signal ground area using a ground plane split line at least 2mm wide or a physical slot. Analog signal ground (AGND) and digital signal ground (DGND) must also be separated.

Choose a single point as the common connection point for all grounds, typically near the ground pin of the power input filter capacitor or the AGND pin of the ADC. Connections can be made using 0Ω resistors, ferrite beads, or small inductors; for example, a CMZ2012A-900T (90μH) can be used to connect AGND and DGND. When all signal lines cross the split gap, there should be a continuous reference plane underneath (such as an unsplit intermediate ground plane), or a bridging capacitor (such as 100pF) should be used to provide a high-frequency return path. With splitting and single-point connection, power ground noise interference to the 16-bit ADC reference can be reduced by more than 40dB.