Plan the manufacturing route
Controlled impedance is a specified electrical property of an interconnect structure. It depends on conductor dimensions, dielectric properties and the nearby reference conductors. Managing impedance starts before routing and continues through fabrication and measurement.
Document each structure
List the relevant layer, single-ended or differential target, reference planes and applicable net classes. Differential pair spacing is part of the structure, not merely a routing preference.
Approve adjustments before release
A fabricator may propose geometry changes to align the design with available materials and finished copper. Review those changes for both impedance and layout constraints before manufacturing begins.
Choose meaningful verification
TDR measurements on representative coupons help verify the fabrication process. A coupon result does not prove every assembled channel meets its complete signal-integrity budget.
Before you request a quote
- State targets and tolerances without relying only on net names.
- Attach the approved stack-up and impedance table.
- Specify coupon placement and reporting.
- Evaluate discontinuities such as connectors, vias and plane changes.
For a build-specific review, provide the actual revision, quantity and delivery requirement. Manufacturing limits, applicable certifications and lead time must be confirmed in the written quotation.