Monday, December 16, 2013

PCB Design Services For Electronics Manufacturers

By Jeannie Chapman


PCB design services require skilled designers who know how to come up with an optimum physical layout for a printed circuit board. They use cutting-edge CAD tools and other PCB design software that helps them create all kinds of board designs. No matter what sort of board and layout is required to be made, it's always going to be a multi-stage designing process starting with schematic capture.

At this point, it would be appropriate to note that the client is usually required to provide the designer with information about at least three basic aspects. One is the aforementioned schematic, although it may also be provided by the client as a netlist file. The netlist is simply a file that contains all the connectivity information for the design, along with descriptions of components used.

The client also has to provide the BOM (bill of materials) that lists all the components to be used and their footprints, although some designers also offer assistance with component footprint capture. Then there's also the board outline that must be provided. The outline, schematic/netlist and the BOM together constitute all the necessary information that will be used for designing the PCB.

Designers start with the netlist or schematic and use techniques such as library development, signal integrity checks, thermal simulation, stress analysis, EMI checking, etc. The series of intermediate steps lead to the development of a file in the gerber format. This is the final end product that designers hand over as a complete PCB image that is directly used in the manufacturing process.

Designers must be able to work on complex solutions involving everything from digital and analog to RF circuits and mixed PCBs. The board can be designed as per specifications as a single or double sided board, or a multi-layered one. The size is also likely to vary, and so will other factors such as component quantities and pin densities.

The designer also has to decide the board characteristics. This is the method that must be used for mounting components and creating circuit traces. The most popular technique that is now in use is called surface-mount technology.

Under this method, end caps will be soldered on the same side of the board as the component itself. This is a huge improvement over an earlier system that made use of through-hole boards. These older boards required the leads to be inserted from one side and soldered on the traces on the board's other side.

Apart from the schematic capture and subsequent board designing steps, the designer may also be called upon to evaluate existing designs, components and footprint captures. Sometimes they're also involved in prototype procurement, and may be asked to do availability checks and collect pricing information against the BOM.

There may, in fact, be other PCB design services required even after delivery of the end product. Customers often need to do minor changes to the design right away and on an ongoing basis, and reorders are also on the cards. Designers are sometimes asked to reverse engineer the process, starting with gerber files. Coming up with a netlist or schematic from a gerber file helps the client rebuild the circuit to implement large-scale changes.




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