specs
- inner layer == 0.5 oz
lamination
The typical lamination order for a 4-layer PCB is:
- Top Layer: Signal layer
- Inner Layer 1: Power plane (e.g., VCC or GND)
- Inner Layer 2: Ground plane (e.g., GND or VCC)
- Bottom Layer: Signal layer
lamination order
"4-layer PCB stack-up:
- Top Layer: Signal
- Inner Layer 1: Power (VCC)
- Inner Layer 2: Ground (GND)
- Bottom Layer: Signal
Please follow this lamination order for manufacturing."
🔄 Typical 4-Layer Stackup (Example)
| Layer | Purpose |
|---|---|
| L1 | Signal (High-speed / Logic) |
| L2 | Ground Plane |
| L3 | Power Plane (3.3V, etc.) |
| L4 | Signal (Slower or routing) |
This stackup helps with:
- Good signal integrity (especially PCIe or USB lines)
- Controlled impedance for high-speed routing
- Noise reduction and EMI compliance
⚙️ Why Use 4 Layers?
| Reason | Explanation |
|---|---|
| Signal integrity | PCIe and USB need impedance control |
| Power distribution | Separate plane ensures clean power |
| Ground return path | Reduces EMI / crosstalk |
| Compact routing | Easier routing in tight Mini PCIe space |
🔧 Considerations
- Use controlled impedance (50Ω for USB, 85Ω diff for PCIe)
- Ensure gold fingers are ENIG plated and follow Mini PCIe spec
- Route high-speed signals on L1 and L4, with ground under them
- Place components only on the top layer, per Mini PCIe mechanical spec
- Follow PCI-SIG or Mini PCIe spec for connector layout and keep-outs