Impedance PCB Calculator


About Impedance PCB Calculator (Formula)

An Impedance PCB Calculator is a tool designed to calculate the characteristic impedance of a microstrip trace on a printed circuit board (PCB). The characteristic impedance represents the ratio of voltage to current in a transmission line and is a critical parameter in ensuring signal integrity and impedance matching in high-frequency electronic circuits. The calculator utilizes the formula for calculating the impedance of a microstrip trace:

Impedance (Z) = [87 / √(ε + 1.41)] * ln[5.98H / (.8W + T)]


  • Z: Characteristic impedance of the microstrip trace.
  • ε: Dielectric constant of the PCB material.
  • H: Height (thickness) of the dielectric substrate.
  • W: Width of the microstrip trace.
  • T: Thickness of the microstrip conductor.

The formula considers the electromagnetic properties of the materials and geometry involved in the microstrip configuration. It is based on empirical approximations and simplifications that provide a good estimate of the characteristic impedance.

The Impedance PCB Calculator is commonly used by PCB designers and engineers working with high-speed digital and analog circuits. Accurate impedance control is crucial to prevent signal reflection, crosstalk, and other undesirable effects that can degrade the performance of electronic systems. By inputting the dielectric constant, trace width, trace height, and trace thickness, the calculator provides a quick and reliable way to determine the required trace geometry for achieving the desired characteristic impedance, ensuring proper signal transmission and signal quality in the PCB design.

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