4Layer PCB: Signal, Manufacturing and Stackup Reference

A 4-layer PCB is widely used in modern electronics design due to its ability to offer an efficient layout for advanced circuit configurations. The stackup for every 4 layer PCB board would typically consists of these functions... In case of you wondering what exactly is stackup for a PCB board, check below:

• Top Layer (Signal): Routes critical signals with short, direct paths to reduce noise.
• Inner Layer 1 (Ground): Serves as a reference ground plane for noise reduction and impedance control.
• Inner Layer 2 (Power): Distributes power to components while reducing noise coupling.
• Bottom Layer (Signal): Complements the top layer by routing less critical signals.

Each layer, thus, would possess a different function. Sometimes, the reason for not making a 2-layer board but choosing to make a 4Layer board is due to the need to hide the ground in inside, i.e. put the grounding in inner layer, so that it would not short circuit if it was installed on metal surfaces; and it will significantly improve signal integrity, reducing EMI (electromagnetic interference).

It improves grounding by ensuring stable reference planes for signals, facilitates power distribution, making it easier to maintain clean, uninterrupted current flow across the board.

By splitting these functions across multiple layers, 4-layer PCBs provide a balanced solution that ensures electrical performance, signal quality, and noise mitigation, making them suitable for everything from consumer electronics to industrial applications.

DFM Considerations

• Material choosing guide: Specs of materials would be your aid. Look for substrate's Electrical, Thermal, CTE properties
• Model performance and compare: Electromagnetic simulation, Noise control, Thermal management, Power source
• Use Symmetric Laminate structures: ground-power-signal
• Testability
• Cost: Factors include (board size, material, volume - prototype/small batch/bulk manufacturing)

Stack-up References for 4-Layer PCBs:

Here are a couple of reference stackups for different thickness 4Layer boards:

4Layer PCB, the finish thickness 0.6mm, using 0.2mm Core and 2*2116 PP

4Layer PCB, the finish thickness 0.6mm, using 0.2mm Core and 2*7628 PP

4Layer PCB, the finish thickness 2.0mm, using 1.6mm Core and 2*7628 PP

4Layer PCB, the finish thickness 2.0mm, using 1.5mm Core and 2*7628 PP

4Layer PCB, the finish thickness 0.6mm, using 1.6mm Core and 2*2116 PP