Month: April 2016

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10 best practices of PCB design

Despite increasing levels of semiconductor integration and readily available systems-on-chips for many applications. In addition to the increasing availability of highly-featured development boards, electronics often still require a custom PCB. Even for “one-off” developments, the humble PCB still performs an important role. It’s a physical platform for a design, and the most flexible for pulling an electronics system together. In this article, we outline ten best practices of PCB design, most of which have stayed consistent for 25 years. These rules are in no particular order and applied to any PCB design project. This should prove as a useful guide both to veteran design engineers as well as makers alike…   Use the right grid Find a grid spacing that suits as many of your components as possible and use it throughout. Although multiple grids may seem appealing. A little additional thought at the early stages of the layout can avoid spacing difficulties and maximize board use. Many devices are available in different package sizes, so use that to your advantage. Furthermore, as the polygon is an important shape when adding copper to your board. Boards with multiple grids will often produce polygon-fill discrepancies, not standardizing on one grid can make your life difficult.     Keep trace lengths as short and direct as possible This rule applies even if it means going back over parts of the layout again to optimize track lengths. This applies particularly in analogue and high-speed digital circuitry where impedance and parasitic effects will always play a part in limiting your system performance.   Whenever possible, use a power plane to manage the distribution of power lines and ground. Using pours on the power plane is a quick and easy option in most PCB design software. It applies plenty of copper to common connections and helps ensure power flows as effectively as possible with minimal impedance or voltage drop. That ground return paths are adequate. If possible, run multiple supply lines in the same area of the board and remember that if the ground plane runs over a large section of one layer. It can have a positive impact on cross-talk between lines running above it on an adjacent layer.   Group related components and test points together Place the discrete components needed for an opamp close to that device so the bypass capacitors and resistors are co-located with it. This helps with the track…