Utilities
For use with High-Speed Digital Design: A Handbook of Black Magic
Over the years I've come to appreciate a good mathematical spreadsheet. With a mathematical spreadsheet tool, you can compose pictures, include explanatory text, and insert "live" equations in a single document. For high-speed design problems, where you need to document calculations pertaining to physical circuit dimensions, the benefits are obvious. Compared to regular spreadsheets, the mathematical spreadsheets have the advantage of showing your work. You can see the equations. So can your co-workers. The mathematical spreadsheet concept is not unique. Math spreadsheet applications are available from several vendors. Popular versions include MathCad, Mathematica, and MatLab. We happen to be MathCad users (although any will accomplish the basic purpose of recording graphics, text and equations). As a result, our collection of high-speed design utilities have been formatted for use with the MathCad application. You will need the MathCad application to run these spreadsheets. If you use a different spreadsheet, it's not hard to convert one format to another.
Formulae and Tools Available to Download
You must have the MathCad application, version 13 or later, for these files to function. If you live in like, Bhutan, or something, and need older-version source code, talk to the webmistress at: info03@sigcon.com.
MathCad scripts
The following MathCad scripts accompany the book High-Speed Digital Design: A Handbook of Black Magic. They are taken directly from Appendix C. Additional examples not in the book are included in these files. The scripts are provided in MathCad syntax, and also in the form of .pdf files in case you want to just see the equations so you can port them to another brand of mathematical spreadsheet.
The .zip file includes a simple short-line transmission line simulator that incorporates the effects of source impedance, load impedance, transmission line delay, characteristic impedance, and risetime of the driving waveform. It does not incorporate skin-effect or dielectric loss. If you want that, look here in the download library for the book :High-Speed Signal Propagation: More Black Magic.- Presentation showing what the simple transmission-line model can do: shortline-presentation.pdf
- Equations used in its model: shortline-equations.pdf
Derivations
The following articles present the motivation behind various equations used in the book:
- Skin Effect Calculations: Special discussion on derivation of Skin Effect Calculations in High-Speed Digital Design: A Handbook of Black Magic.
- Resistance: Concerning the derivation on page 414 of the equation for calculating the DC resistance of power planes based on the diameters of two contact points space at X amount of distance. (newsletter v1-11)
- Ground-bounce calculations: On page 62 of the High-Speed Digital Design Text… where does the factor of 1.52 come from? (newsletter v1-12)
- Equiv. Circuit Source Impedance: What is the true source impedance of the equivalent circuit at figure 1.6 (page 13)? (newsletter v2-09)
- Via Capacitance: On page 257, formula [7.6] for the capacitance of a via is a crude approximation--I've now got some better material. (newsletter v5-09)
- Via Inductance: On page 259, formula [7.9] glosses over the location of the signal return current associated with the via. A full discussion of the issue is now available. (newsletter v6-04)
Errata Page
Applies to all printings. Download here.