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Trace Impedance Calculator

Ω
= 1.37 mil
mil

203.2 µm

mil

254.0 µm

Z₀73.0Ω
εᵣ eff3.19
Delay152ps/in
For Z₀ = 50Ω → w = 16.775 mil (426.073 µm)

Microstrip Cross-Section

Ground Plane (Cu)Substrate (εᵣ)Signal Tracew = 8.0 milh = 10.0 milt
Characteristic ImpedanceZ₀ = 73.03 Ω

Approximation only. Use a 2D field solver for critical designs. Better yet, use this as a starting point and let your PCB fab house dial in the exact stackup. They do this all day, every day.

Show formulas

Microstrip (IPC-2141):

Z0≈87εr+1.41ln⁡(5.98h0.8w+t)Z_0 \approx \frac{87}{\sqrt{\varepsilon_r + 1.41}} \ln\left(\frac{5.98h}{0.8w + t}\right)

w = trace width

t = trace thickness (copper)

h = substrate height (dielectric thickness)

εᵣ = dielectric constant

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