Differential Impedance Calculator
Current version: 3.11

(If you need support for versions 2.2 and earlier of the calculator, go here.)

UltraCAD's new Differential Impedance calculator will calculate single-ended and differential impedance for the common configurations we all deal with:

            Microstrip
            Embedded Microstrip
            Stripline
            Edge-coupled Asymmetric Stripline
            Broadside-coupled Asymmetric Stripline

Given a value for impedance, it will (in most cases) calculate the other variables we need during the design process. So it will help answer questions like:

        What width trace do I need to hit a 75 Ohm differential impedance?
        How far apart do my planes need to be?
        How sensitive is my design to variations in Er?
        Will a change in trace thickness impact my design?

In addition, the calculator calculates propagation time, Co, and Lo for the traces. While our earlier calculator does some of these things, it is based on a different calculational technology and is not nearly as accurate as this new version is. The older calculator will likely be phased out as the new calculator gains acceptance.

Beginning with version 2.01, UCCALC also calculates common mode impedance.

Beginning with Version 3.0 the licensing procedure changed dramatically. A dongle is no longer required for the calculator. Instead, a simple license file is required, which UltraCAD can send to you by e-mail.

Beginning with Version 3.0, all files may be placed in a folder selected by the user. C:\uccalc\ is a good choice.  The license file must be placed in EITHER of these directories.
    The root directory of your system drive (typically  c:\   )  or
    A   \uccalc\ subfolder under the root directory of your system drive (typically c:\uccalc\)

Also beginning with version 3.0 the freeware option for single-ended traces is no longer available.

Version 3.11 corrects a couple of minor calculational errors and makes the calculator "internationally aware" in that it now recognizes your local custom for decimal separator (period or comma) and adjusts accordingly.

Free Upgrade Offer: If you have a license dongle for version 2.2 or below, we will exchange the dongle for a license file for the newer version 3.11. Return the dongle to us along with a license form with your current information and indicate in the comments section that this will be a free upgrade.

Click here to see a .wmv video describing this calculator. (Approx. 4 MB, 3 minutes) Important Note:  This video describes version 2.2 and is slightly out of date. What it describes about the calculator is correct. But it references a license dongle (which has been replaced by a license file) and it references a freeware version which is no longer applicable.

Go to this page for download information, including how to download the Operator's Manual. The Operator's Manual is a *.pdf version of the help file and describes the calculator in detail, including its specifications.

Go to this page for some screen shots of some sample calculations.

Go to this page for licensing information and instructions on how to acquire your license.

This calculator is designed to run on Windows 98/ME/NT/2K/XP/VISTA/Win7, 32 bit and 64 bit versions.

Click on logo to return to UltraCAD's Calculator page.