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In this article, we'll discuss seven basic (but critical) tips and strategies for beginners and masters alike. Pay attention to these tips during your design process, and you'll reduce spins, design times, and overall diagnostic hair-pulling for you and your team. So let's get started.
BONE UP ON FABRICATION METHODS AND FAB CHEMISTRY
In this era of fabless IC companies, it isn't all that surprising how many engineers don't actually know the steps and chemistry involved in creating PCBs from their design files. This lack of practical knowledge can often lead a newer designer to make design choices that are more complicated than necessary. For example, a common novice mistake is to lay the board out in extremely precise geometries, using orthogonal trace bends on tight grids, only to find out that not every board shop has the capabilities to produce the design with sufficient reliability to sustain a lifetime in the field. The shops that do have these capabilities may not provide the most economical pricing for the PCB. Did the design really need to be that complex? Could the board have been laid out on a larger grid, reducing the cost of the boards and improving the reliability? Other pitfalls for novice designers are unnecessarily small via sizes, and blind and buried vias. These advanced via structures are great tools in the PCB designer's toolbox, but highly situational in their effectiveness. Just because they are in the toolbox doesn't mean they should be used.
Bert Simonovich's "Design Notes" blog has this to say about via aspect ratios: "A via aspect ratio of 6:1 pretty much ensures your board can be fabricated anywhere" (http://blog.lamsimenterprises.com/2011/02/15/pcb-vias-an-overview/). For most designs, with a little thought and planning, these HDI characteristics can likely be avoided, which again will save cost and improve manufacturability of your design. The physics and fluid dynamics required to copper plate these ultra-small or dead-ended vias is not something that all PCB shops specialize in. Remember, it only takes one bad via to render the entire board useless; if your design has 20,000 vias in it, you have 20,000 chances for failure. Include HDI via technology unnecessarily, and the chances of failure just went up.
TRUST THE RAT'S NEST
Sometimes it just seems like...