PCB design golden rule never changes
Although semiconductor more integrated, systems have many applications are readily available on-chip, but many powerful and out of the box more and more development board can easily obtain, but in many cases the use of electronic application products still you need to use a custom PCB . At one time in development, even an ordinary PCB can play a very important role. PCB is designed physical platform, but also for the original components of the electronic components of the most flexible system design. This article will introduce several PCB design golden rule, these laws since 25 years ago, commercial PCB since the birth of design, mostly without any change, and widely applicable to various PCB design projects, whether young or electronic design engineer more mature a circuit board manufacturer, are of great guiding role.
The following article describes the electronic design engineers use design software for PCB remember and practice of design and layout should be commercially manufactured ten most effective design rules. Engineers do not need to chronological order or the relative importance of the implementation of these rules, just follow all can dramatically change the product design.
Rule 1: Choose the correct mesh - Set up and always capable of matching grid spacing element. Although the multi-grid utility seems obvious, but if the engineer PCBThe initial layout can think more about some of the problems encountered can be avoided and maximize the application circuit board when the interval. Since many devices are available in a variety of package size, engineers should be most conducive to their own designs. Further, the circuit board copper polygon essential multigrid circuit boards polygons filled polygon is performed will generally have variations, although not based on a single grid then the standard, but may be provided beyond the desired useful life of the circuit board .
Rule two: Keep the shortest most direct path. This unusual sounds simple, but it should be at each stage, even if the means to change the circuit board layout to optimize wiring length should be kept in mind. This system is also particularly suitable for the performance is always limited by the impedance portion and parasitics analog and high speed digital circuits.
Rule three: as a power supply layer using the distribution management of the power line and ground. Power for most copper layer PCB design software is also faster simpler option. Large number of conductors carried by a common connection, can ensure maximum efficiency or pressure drop and having a minimum impedance of the current , while providing sufficient ground return path. If possible, the plurality of power supply lines can also run in the same region of the circuit board, to confirm whether a ground layer covering the PCB most level of a layer, it is a good interaction between adjacent layers on the work line.
Rule 4: The relevant elements are grouped together with a desired test point. For example: The OpAmp operational amplifier discrete components desired from the device is placed in the part close to shunt capacitors and resistors can be co-located therewith, to help optimize the wiring length mentioned two rules, while also allowing testing and fault detection it easier.
Rule five: the desired repetition copy board another many times larger circuit board PCBImposition. Choose the most suitable size used by the manufacturer of the device helps reduce prototyping and manufacturing costs. First performed on the panel circuit board layout, the circuit board contact the manufacturer to obtain their preferred sizes of each panel, and then modify your design specifications, and try to be repeated several times in your design within these panel sizes.
Rule six: integration component values. As a designer, you can select some elements or high or low, but performance as discrete components. By integration, simplified bill of materials in a smaller standard value, and may reduce costs. If you have a series of devices based on the preferred value of PCB products, then the longer term perspective, but also more conducive to you to make the right inventory management decisions.
Rule Seven: as much as possible to perform design rule checking ( DRC ). Although the PCB is running on software DRC function only takes a very short time, but in a more complex design environment, as long as you always check is performed during the design process can save a lot of time, which is a good habit worth keeping. Each routing decisions are critical, by performing the DRC can always remind you that the most important wiring.
Rule eight: flexible use of screen printing. Screen printing can be used to label a variety of useful information to a circuit board manufacturer, service, or test engineer, installer or commissioning personnel future use. Clearly labeled only functional test points and labels, but also as the marking device and the connector direction, even these comments printed circuit board element for use in a lower surface (after the circuit board assembly). In the application of the full circuit board surface screen printing technique to reduce duplication and to streamline the production process.
Rule 9: Required decoupling capacitors. Do not try to avoid by decoupling the power cord and limits based on component data table to optimize your design. CapacitorInexpensive and durable, you can spend as much time will be good capacitor assembly, while adhering to the law Sixth, use the standard value in order to maintain inventory and tidy.
Ten rules: generating a PCB manufacturing parameters and verify before submission production. While most circuit board manufacturers are happy to help direct you to download and verify, but you would be best to output Gerber files, and check and as expected with a free viewer, to avoid misunderstandings. By personally verify, you may even find that some of the careless errors, and thus avoid complete production losses in the wrong parameters.
Because the circuit design shared more widely, and internal teams increasingly rely on reference design, similar to the above basic rules will remain a feature of the printed circuit board design, we believe that for the PCB design is very important. Clearly these basic rules, developers can very flexibly enhance the value of their products and get the maximum benefit from circuit board manufacturing. Even novice board design, as long as these basic rules to keep in mind will be able to speed up the learning process and boost confidence.
Edwin Robledo Profile:
Edwin Robledo in 1991 Bachelor of Electrical Engineering, University of Puerto Rico. After graduation worked at a number of companies as a consultant jobs, especially in the field of communications companies. Edwin Robledo in 1993 Nian 5 joined the CadSoft team, has participated in the development of lifting CadSoft new feature, currently serves as general manager of the US office. " InCadSoft team, the most interesting work than be content to communicate with the user. Their opinions and encourage us much moved.