The sixth edition of the Printed Circuits Handbook just arrived at my office where it is taking up considerable desk space. The almost 2.5 in-thick tome dwarfs the 2 in-thick fifth edition, which I reviewed in 2002. My fourth edition handbook (copyright © 1996) is only 1-3/4 inches thick, which in turn makes my second edition handbook’s (copyright © 1979) 1-1/4 in thickness look skinny, let alone the smaller format page size.

The Printed Circuits Handbook has been a classic reference to the industry for many years, and the new edition will assure its place for years to come.

Clyde dropped the so familiar possessive prefix “Coombs'” from the handbook title, yet, as always, Clyde F. Coombs, Jr.’s role is that of editor-in-chief for the 67 chapters and 44 contributors to the new edition. The list of contributors reads like a who-is-who in the world of printed circuit boards. Clyde explained to me that without the Coombs in the title, an Amazon search leads more reliably to the latest edition. Strange things happen!

As in the past, each edition has a theme for the new material that is covered and reflects the changes in the industry since the precious edition. On balance, this adds material, hence the volume increase mentioned earlier. While the technology is evolving and changing, old processes and material sets hardly ever completely disappear, so there is little opportunity to drop chapters without compromising the concept of a handbook. This edition’s new material theme is Restriction of Hazardous Substances (RoHS) in general and lead-free in particular. In addition, there is a substantial update and expansion to Happy Holden’s high-density interconnection (HDI) section that consists of two chapters, the first one offering an Introduction to HDI technology, followed by a chapter on advanced HDI technologies. Of course, all other chapters have also undergone considerable updates.

The chapters are arranged in 15 parts that mostly follow the chronology of design, data exchange, planning for fabrication and assembly, material selection, the process flow through fabrication, assembly, quality control, and reliability testing. Issues specific to flex circuits are covered in Part 15.

In his preamble, Clyde points out the impact of RoHS and lead-free in particular, not only on the selection of lead-free alloys but the entire fabrication process. He does it matter-of-factly, leaving it to the reader to judge if the mandated changes will lead to the intended benefits to society. He also draws our attention to the new coverage of embedded components and conformal coatings.

I had lamented a minor flaw in the fifth edition, namely that some black and white illustrations were a bit fuzzy and difficult to decipher. It was a pleasant surprise to see all illustrations in the new edition of good quality. In summary, the latest edition of the Printed Circuits Handbook is a great reference book for the PWB engineer and anyone who wants to gain in depth knowledge of PWB technology.