Printed Circuit Design & Fab Online Magazine - Current Issue

Material Matters

Bill Hargin When sourcing materials, consider dual-ply glass.

Au: This column is a comprehensive follow-on to the July column introduction on glass-weave skew and the discussion in August and September of various mitigation strategies. With some overlap, these may be read together or independently.

In my July article, Part One of a series on glass-weave skew, I introduced its causes and when or why a hardware designer might care. In Part Two I discussed various mitigation techniques and cost. Part Three presented a deeper dive into the impact of glass styles on precipitating or mitigating skew. Part Four will cover dual-ply and low-Dk glass.

While glass-weave skew (GWS) is a real problem, it’s hard to characterize because it is statistical in nature. What is the chance one line in a pair will see a different dielectric constant than the other? It depends on the pitch of the lines, the length of the lines, the laminate composition, and the relative chance alignment of the glass bundles under the two lines.

Read more: How to Avoid Getting Totally Skewed, Part Four

Mitigation techniques and costs of designing around glass-weave skew.

Read more: How to Avoid Getting Totally Skewed, Part Three

Bill Hargin Mitigation techniques and costs of designing around glass-weave skew.

Au: This column is a comprehensive follow-on to the July column introduction on glass-weave skew. With some overlap, these may be read together or independently.

In my July column, I introduced the causes of glass-weave skew (GWS) and when or why a hardware designer might care. In part two here, we discuss mitigation techniques and cost. In part three, we’ll do a deeper dive on the impact of glass styles on precipitating or mitigating skew.

While it is a real problem, it’s hard to characterize because it is statistical in nature. What is the chance one line in a pair will see a different dielectric constant than the other? It depends on the pitch of the lines, the length of the lines, the laminate composition, and the relative chance alignment of the glass bundles under the two lines.

Read more: How to Avoid Getting Totally Skewed, Part Two

Bill Hargin The first of a three-part series on designing around glass-weave skew.

Au: This column is a comprehensive follow-on to our June column. With some overlap, these may be read together or independently.

In June I discussed the differences between 1067 and 106 glass styles, introducing the concept of “glass-weave skew” or the “fiber-weave effect.” Here in part one of a series on glass-weave skew, I’ll introduce its causes and when or why a hardware designer might care. In part two, we will discuss mitigation techniques and cost, and in part three we’ll do a deeper dive on the impact of glass styles on precipitating or mitigating skew.

First, a memory. While writing this, I kept thinking of my first time on the German Autobahn, in the late 1990s. We were coming back from a HyperLynx SI workshop and – as weird as it sounds even 20 years later – my driver was going just under 240kph (~150mph). As the semi-naive American in the car, I thought I should offer some chitchat on the four-hour drive to Munich to keep the driver awake. In an almost robotic tone, my German counterpart said, “I cannot talk at this speed.” I don’t suppose I’ll ever forget that comment.

Read more: How to Avoid Getting Totally Skewed