What this tool does

Unlike standard calculators that ask for a trace width and output an impedance, this tool works in reverse. It acts as a multi-layer geometric solver. You select a target impedance (e.g., 90ohms Diff for USB), define the dielectric heights and copper weights of your stackup, and the engine calculates the exact Trace Width ($W$) and Pair Spacing ($S$) required on every single routing layer simultaneously.

How to use it

1. Select a Protocol: Choose from the preset list (USB, PCIe, Ethernet, etc.) to automatically load the industry-standard target single-ended ($Z_0$) and differential ($Z_{diff}$) impedances.
2. Define your Stackup: Add the routing layers of your PCB.
   • For top/bottom layers, choose Microstrip and enter $H_1$ (distance to the nearest reference plane).
   • For internal layers, choose Stripline and enter $H_1$ and $H_2$ (distance to the upper and lower reference planes respectively).
3. Read the Output: The Required W and Required S columns will dynamically update with the exact trace geometry needed for each layer.

The Mathematics (IPC-2141)

Because the standard IPC equations compute impedance from width ($Z = f(W)$), this tool uses a computational binary search (bisection method) to invert the equations and solve for $W$ and $S$ iteratively until the target is hit.