Geometric Parameter Definitions
| H (/H1)
||height of trace or dielectric above return plane
||distance between the differential stripline pair
||relative permittivity of the dielectric
Electrical Parameter Definitions
||effective characteristic impedance including the capacitance of distributed loads
||inductance per unit length
||capacitance per unit length
The source for formulas used in this calculator (except where otherwise noted) is:
IPC-D-317A, Design Guidelines for Electronic Packaging Utilizing High-Speed
Techniques, Jan 1995; Section 5, pp. 13 - 36.
THESE FORMULAS ARE APPROXIMATIONS!
They should not be used when a high degree
of accuracy is required.
The transmission line calculator concept was developed by Douglas Brooks and is
described in his paper:
PCB Impedance Control: Formulas and Resources, Printed Circuit
Design Magazine, March 1998.
A copy of his paper and a similar transmission line calculator that runs on a PC can be obtained
from UltraCAD Design, Inc.