PCB Stackup and Impedance
Agree the PCB stackup before relying on controlled-impedance geometry. Layer order, dielectric materials, copper and finished thickness form one construction; a drawing, CAD assumption and supplier proposal should not describe different boards.
Requirements for an engineering review
| Topic | Information to supply | Decision to confirm |
|---|---|---|
| Layer definition | Signal/plane order, reference planes and copper distribution. | Resolve the electrical and fabrication construction together. |
| Dimensions | Dielectric and copper thickness in µm or mm; finished board thickness in mm. | Use stated units and consistent finished/starting definitions. |
| Impedance | Target in Ω, tolerance and single-ended or differential geometry. | Confirm material assumptions, field calculation and verification. |
| Release | Approved stackup revision, coupon or report requirements. | Document approval before routing or fabrication is released. |
How to confirm the applicable range
Send the current revision and the limits that matter to your product. The review should identify the responsible manufacturing site or supply partner, the agreed conditions and the approval needed for exceptions. Keep the confirmed range, source and review date with the released project records.
Release checklist
- Resolve conflicting notes or units before the order is released.
- Confirm whether the requirement is routine, requires an engineering trial or is outside the proposed scope.
- Agree inspection or verification evidence and the owner of unresolved design decisions.
Prepare the next project decision
Continue with PCB Manufacturing Services, PCB Fabrication Capability, PCB Material Selection, PCB Design Capability.
Read the related purchasing checklist.
Discuss your revision, quantity and project requirements. Early enquiries are welcome when some files or requirements are still being prepared.
