Please enter all required values.
RESULTS
Input Parameters Specification
Trace ThicknessCopper thickness of each coupled stripline conductor. Thicker copper changes the effective conductor geometry and affects calculated impedance.
Substrate HeightTotal stripline dielectric height between reference planes. This is a key stack-up dimension for controlled impedance routing.
Trace WidthWidth of each edge-coupled trace. Wider traces generally reduce impedance in the stripline structure.
Trace SpacingGap between the two coupled traces. Smaller spacing increases coupling and changes odd/even mode impedance.
Dielectric ConstantRelative permittivity of the PCB material. FR4, Rogers, PTFE and other laminates can produce different impedance results.
Output ImpedancesThe calculator returns odd, even, common and differential impedance for edge-coupled stripline differential pair design.
Practical Operational Examples
Differential Pair Design
Estimate differential impedance for edge-coupled stripline routing inside multilayer PCBs used in USB, LVDS, Ethernet, HDMI and high-speed serial links.
Signal Integrity Matching
Adjust trace width, spacing and dielectric height to target odd-mode, even-mode, common-mode or differential impedance values.
PCB Stack-Up Review
Check how dielectric constant and substrate height affect impedance before sending a controlled-impedance board for fabrication.
Routing Trade-Off
Compare wider traces with larger spacing versus narrow traces with tighter coupling to understand routing and impedance margin.
Diagrams & Theory
Edge-coupled stripline uses two traces embedded between top and bottom reference planes. Odd and even modes combine to give differential and common impedance. In odd mode, the two traces carry opposite-polarity signals; in even mode, both conductors move together. These modes are important for differential pair routing and controlled impedance PCB design.
Formulas & Mathematical Logic
Step 1: Convert trace thickness, substrate height, trace width and spacing using the selected unit multipliers.
Step 2: The calculator uses the original edge-coupled stripline impedance JavaScript formula from your uploaded source.
Step 3: Odd-mode impedance is calculated from the coupled stripline geometry and dielectric constant.
Step 4: Even-mode impedance is calculated from the same geometry with even-mode field behavior.
Step 5: Common impedance = Even impedance / 2.
Step 6: Differential impedance = 2 × Odd impedance.
Practical meaning: smaller spacing increases coupling, which strongly affects odd and differential impedance.
Step-by-Step Example
Example: trace thickness = 1 mil, substrate height = 20 mil, trace width = 8 mil, trace spacing = 8 mil, dielectric constant = 4.2.
The calculator first converts each geometric input using the selected unit multipliers.
The single stripline behavior is estimated internally from width, thickness, height and dielectric constant.
The coupling between both edge-coupled traces is evaluated from spacing and trace geometry.
Odd and even impedance values are calculated first.
Common impedance and differential impedance are then derived from even and odd impedance values.
How to Use This Calculator
Enter copper trace thickness and choose the correct unit.
Enter substrate height between reference planes.
Enter trace width for each coupled stripline conductor.
Enter spacing between the two traces.
Enter dielectric constant of the PCB laminate.
Click Calculate to get odd, even, common and differential impedance.
About This Calculator
Design controlled-impedance edge-coupled striplines for differential PCB routing.
The CalcBoy Edge Coupled Stripline Impedance Calculator estimates odd-mode, even-mode, common-mode and differential impedance from copper thickness, substrate height, trace width, spacing and dielectric constant.
Edge-coupled stripline routing is widely used when a differential pair must be routed inside a multilayer PCB between reference planes. Unlike a single-ended trace, a differential pair has two important modes. Odd mode appears when the two traces carry equal and opposite signals, while even mode appears when both traces move together. These modes define the differential and common impedance values used in high-speed PCB design.
This calculator is useful for controlled-impedance layouts such as USB, LVDS, Ethernet, HDMI, SERDES, RF differential routing, clock pairs and high-speed digital boards. By changing trace width, spacing, dielectric height or dielectric constant, you can see how the impedance results move before final PCB fabrication.
For production designs, always compare calculator output with your PCB manufacturer’s stack-up and impedance solver. Copper plating, solder mask, resin content, glass weave and fabrication tolerance can shift real impedance from the estimate.
Best UseEdge-coupled stripline differential pair impedance checks.
Supported OutputsOdd, even, common and differential impedance.
Helpful ForUSB, LVDS, Ethernet, HDMI, SERDES, RF and high-speed PCB routing.
Design ReminderTrace spacing strongly affects coupling and differential impedance.
Tip: For a real controlled-impedance PCB, send your target differential impedance and stack-up request to the board manufacturer before final routing.
Frequently Asked Questions
What is edge-coupled stripline impedance?
It is the impedance of two adjacent stripline traces embedded inside a PCB between reference planes.
What is odd-mode impedance?
Odd-mode impedance is the impedance seen when the two coupled traces carry equal and opposite signals.
What is differential impedance?
Differential impedance is twice the odd-mode impedance for a coupled differential pair.
What is common impedance?
Common impedance is derived from even-mode impedance and represents the pair when both traces move together.
Does spacing affect differential impedance?
Yes. Smaller spacing increases coupling and can significantly change odd-mode and differential impedance.
Can this replace a PCB manufacturer impedance report?
No. Use it for design estimation. Final production impedance should be confirmed with the PCB manufacturer’s stack-up and impedance calculation.
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