UltraCAD Design, Inc


Other Articles and Misc


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The Effects of Vias on PCB Traces  
  This was UltraCAD's first PCB-based article. UltraCAD was given a grant by the Washington Technology Center to study the effects of vias on printed circuit boards. The results were surprising. This article, reprinted in the August, 1996, issue, discusses the research and the results.
90 Degree Corners: The Final Turn.   
  This article, from the January, 1998, issue, explores the question of whether 90 degree corners on traces create an unacceptable change in impedance or EMI emissions compared to mitered corners. It should have been the final word on this topic (but it wasn't!)
This Month's Quiz.  
  When a device switches some current down a trace very quickly, where do they electrons (current) come from to support that sudden requirement? From The power supply? From the planes? From bypass caps? If so, which ones? Take the quiz (adapted from a column in the January, 2000 issue) and see if you can figure it out!
Propagation Time.  
  What determines how fast a signal flows through a wire or a trace? In particular, would signals travel at the same speed if a wire were submerged under water? Take this quiz, from the August, 2000 issue, and find out why or why not.
Splitting Planes for Speed and Power.  
   This article appeared as a feature article in the December, 200 issue of the magazine. It discussed why planes might be split in the first place, and then if they are, what kinds of design rules might follow.
When Signal Integrity Matters  
  We are often asked, "When does signal integrity become a problem?" This article, from the October, 2001, issue, answers this question (we hope!)
Lessons Learned Along the Way:  RFI Control  
  In a somewhat nostalgic look back in his career, Doug Brooks writes about lessons learned in the September, 2002 issue. He concludes with this as one of the morals on the story:  "A good technician with experience can be more valuable than someone else with all the degrees in the world!"
Controlling Radiated EMI Through PCB Stackup --- Rick Hartley.

This article, authored by Rick Hartley, first appeared in Printed Circuit Design Magazine in July, 2000. I have always considered it a classic. While it is written from the relatively narrow aspect of “controlling EMI,” the conclusions re board stack-up have relevance for almost all signal integrity issues, from EMI to Crosstalk to Power Distribution Systems (i.e. bypass capacitors). The bottom line conclusion is (1) route every trace directly over and close to a related, continuous plane, and (2) provide at least one Pwr/Gnd planar pair for planar capacitance. It is reprinted here on our web pages by permission.


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