Let's continue to learn about the digital ground and analog ground.
In PCB design and manufacturing, separating analog and digital ground planes is a common practice to reduce crosstalk between analog and digital circuits. By defining separate analog and digital grounding sections, it becomes easy to determine in the schematic which components and pins should be connected to the digital ground section and which should be connected to the analog ground section. This design approach allows for routing with two distinct ground planes as references, effectively reducing noise.
The two ground planes should be accurately placed, ensuring that digital and analog components are positioned beneath their respective ground planes, as shown in the cover diagram. This layout helps minimize current in ground loops and reduces electromagnetic interference (EMI) caused by discontinuities in the ground planes.
In mixed-signal circuits, although analog and digital grounds are physically separate, they need to be connected at a single point. Doing so provides a low-impedance path to reduce noise caused by voltage differences between the ground planes. In the schematic, it is recommended to place ferrite beads or 0Ω resistors between the analog and digital sections to achieve this single-point connection.
The merging of digital and analog grounds should be placed close to integrated circuits. In mixed-signal designs with separated planes, digital signals should not be routed through the analog ground plane, and analog signals should not be routed through the digital ground plane. This routing strategy helps maintain signal integrity and reduces noise due to cross-coupling between the ground planes.
