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44 DESIGN007 MAGAZINE I MAY 2021 space not adequate between SMD pads to be able to have higher copper. ese both hap- pen frequently and must be leveraged to have a good design solution. ose of you who have read my columns when I worked in board fabrication know this is something I feel strongly about and is a bit of a soapbox for me. Even 0.003"/0.003" trace and space on a half-ounce foil to start can be a fabricator limitation. Some fabricators will then ask to start on one-quarter or 3/8 th -ounce foil to be able to deal with the trace and space that low, remembering that starting on even a half-ounce will require a half-mil etch com- pensation, taking the space down to 0.0025". At this point, most fabricators require starting on the lighter copper weights of either quar- ter or 3/8 ounce. ese are such light copper weights that most fabricators' etchers can easily etch that thinness of metal without an additional etch compensation digging into the available space. Finally, by far the most important… #1: Reading Our Customers' Minds About this, Jeff Reinhold said: "We oen have many inputs to deal with. Some are more difficult to decipher than oth- ers, but if they are available, we can read them. What we can't read is our customer's minds. When we get right down to it, this is what our job is—create data that can be used to build a circuit board, and that meets or exceeds our customer's expectations for how that should be implemented (i.e., read the customer's mind). I used to say that there are 500 ways to lay out a board and all of them will work, but only one of them fits what is in the customer's head. at is still true but now the number is probably more like 20 than 500." In short, good design makes a product use- ful. It has to satisfy certain criteria—not only the functional, but also the psychological and aesthetic. Good design emphasizes the useful- ness of a product while disregarding anything that could possibly detract from it. Jeff continues: "Our customers invariably have some picture in their head (or collective heads) of what they think the layout should be or will look like. Not only do we have to figure out what that is, via additional conversations or use of the tools at our disposal, we must balance that with our own knowledge of best practice for the given circuit and our customer's ideas on implementation, and then be able to create something that meets their expectations, even if it must be something different than what they thought it would be." Jared Spool, the American writer, researcher and usability expert, said: "Good design when it's done well, becomes invisible. It's only when it's done poorly that we notice it." [1] Another favorite quote about design comes from Steve Jobs: "Design is not just what it looks like and feels like. Design is how it works." [2] But my favorite quote comes from "Wind, Sand and Stars" by Antoine de Saint-Exupéry: "A designer knows he has achieved perfection not when there is nothing le to add, but when there is nothing le to take away." [3] DESIGN007 References 1. Lesson From A Good Bad Design. 2. "The Guts of a New Machine," The New York Times Magazine, Nov. 30, 2003. 3. "Land of Men," Antoine de Saint- Exupéry, 1939. Mark Thompson, CID+, is a senior PCB technologist at Monsoon Solutions Inc. To read past columns or contact Thompson, click here. Thomp- son is also the author of The Printed Circuit Designer's Guide to… Producing the Perfect Data Package. Visit I-007eBooks.com to download this book and other free, educational titles.