PCB stackup example – minimum track, clearance, VIA …
Here is the PCB stackup what I normally start with + requirements for minimum VIA, track, clearance and impedances.
- 12 Layers:
- L1 – Signal
- L2 – GND
- L3 – Signal
- L4 – Signal
- L5 – GND
- L6 – Powers
- L7 – Powers
- L8 – GND
- L9 – Signal
- L10 – Signal
- L11 – GND
- L12 – Signal
- Required impedances
- Single ended: 50 OHMs (all signal layers)
- Differential: 70, 90 and 100 OHMs (all signal layers)
- Other requirements
- Minimum through-hole VIA: 0.45mm (pad) / 0.2mm (drill)
- Minimum track / clearance: 0.1 mm / 0.1 mm (more expensive PCB: 0.075mm / 0.075mm)
- If uVIAs are used
- uVIA: 0.25mm (pad) / 0.1mm (laser drilled hole)
- buried VIA: 0.45mm (pad) / 0.2mm (drill)
I also found useful information about HDI stackups in this Mentor document: HDI Layer Stackups for Large Dense PCBs
HDI PCB technology comparison (picture from the Mentor document)
HDI PCB technology comparison (picture from the Mentor document)
