EMC Laboratory
4000 Enterprise Dr.
Missouri University of Science
and Technology
Rolla, MO 65401
emclab@mst.edu
PCB Trace Impedance Calculator
Calculates the characteristic impedance and perunitlength parameters
of typical printed circuit board trace geometries.
Select a configuration:
Microstrip Trace
Embedded Microstrip Trace
Stripline Trace
Dual Stripline Trace  Geometric Parameter Definitions:
W:   trace width  T:  trace thickness  H (/H1)  height of trace or dielectric above return plane  C:  distance between the differential stripline pair  er:  relative permittivity of the dielectric 
Electrical Parameter Definitions:
Zo:   characteristic impedance  Zc:  effective characteristic impedance including the capacitance of distributed loads  Tpd:  propagation delay  Lo:  inductance per unit length  Co:  capacitance per unit length 
Acknowledgements: The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing HighSpeed Techniques (4th Working Draft, IPC2251, February 2001. THESE FORMULAS ARE APPROXIMATIONS! They should not be used when a high degree of accuracy is required. This transmission line calculator was based on a concept developed by Douglas Brooks of UltraCAD Design, Inc. 
