Good Practices for Multilayer PCB Design
In the space-constrained embedded system, more functional packaging requirements can be solved by multilayer PCB design. Each additional layer will add additional manufacturing processes resulting in the cost of the PCB itself. When designing multilayer PCB electronics, PCB designers should keep in mind some good practices.
Blind Vias and Buried Vias
Blind vias and buried vias are common useful functions that you can implement in your multilayer PCB design. Blind vias are vias that are visible from one side of the PCB and terminates in the inner layer. While buried vias are vias that interconnect the inner layer. In the high-density design, these special vias are very useful, though manufacturing costs are higher.
Digital and Analog Ground Separation
Choosing a multilayer design does not mean that basic PCB best practices should be ignored. Proper ground separation is important to ensure that digital circuit does not interfere with the analog signal. Single point connections are usually recommended to keep analog and digital ground apart.
Inner Ground and Power plane
It’s a common rule that adequate ground and power plane is required for a stable and functional circuitry.
In a space-constrained design, the power and ground planes may not have enough space. Therefore, place the ground and power plane on the inner layer is commonly used in multilayer PCB design. In addition to providing a stable voltage, it also releases the valuable space on the outer layer for other signals.
Use Inner Layer for EMI Protections
EMI is a common problem in various PCB designs. EMI-susceptible electronic components can be very unstable. A 6-layer PCB can be used to protect the sensitive signal from EMI, where the signal can be routed in the middle layer adjacent to the power and ground planes. High-speed and differential signals are usually placed in the middle layer of EMI protection.