Defined Impedance made simple

PCBs with defined impedance don’t have to be complex or expensive. With the DEFINED IMPEDANCE pool, Eurocircuits provides a precise, repeatable, and cost-effective solution for moderate high-speed designs.
Based on standardised FR-4 stackups, verified material data, and controlled processes, we achieve stable impedance values within a ±10 % tolerance – reliably manufactured and clearly documented.

Why impedance control matters

As signal frequencies increase, even small variations in track width, layer thickness, or dielectric properties can affect signal quality. Stable impedance is essential to prevent reflections, crosstalk, and signal loss – especially in high-speed designs such as USB 3.0, HDMI, or 5G.

👉 For a detailed explanation of what “defined impedance” means in PCB manufacturing, see: Defining Defined Impedance

Standardised solution instead of custom builds

With the Defined Impedance pool, Eurocircuits offers predefined 4-, 6-, and 8-layer FR-4 stackups. Each buildup is based on verified dielectric constants and carefully controlled layer thicknesses.This ensures stable and predictable impedance values – without expensive high-frequency materials or custom configurations.

Predefined buildup

• Standard FR-4 material (IS400)
• 120 µm prepreg on top and bottom outer sections
• Impedance tracks on outer layers – reference plane on inner layer 1
• Repeatable impedance within defined margins
• Cost- and price-effective solution
• Suitable for designs within Pattern Class 6/7

Designer’s Tip: Use the standard poolable stackups in our DEFINED IMPEDANCE pool service together with our built-in Impedance Calculator to define your PCB design parameters before you start your layout.

Benefits:

• Repeatable results through standardised processes
• FR-4 materials with verified εr values
• Consistent impedance within ±10 % across multiple production runs

👉 See all details: DEFINED IMPEDANCE pool Service

Design support with real manufacturing data

The Online Impedance Calculator uses exactly the same material data and stackups as the DEFINED IMPEDANCE pool This allows designers to define track and gap values for 50 Ω (single-ended) or 90 Ω (differential pair) using real manufacturing parameters.

If the design rules are respected, the resulting impedance on the finished PCB will remain within the specified ±10% tolerance window. Together with the PCB Visualizer, it provides a consistent, data-driven workflow – Right First Time for Manufacturing.

👉 Try the impedance calculator: Defined Impedance Calculators