Sunday, December 15, 2013

PCB Design Services And Solutions

By Jeannie Chapman


PCB design services must be provided by skilled professionals with enough experience to come up with the optimum physical layout for a client's printed circuit board. They must have the resources and capability to deploy the latest CAD software and other PCB design tools to handle complex designs and all kinds of boards. Generally speaking, the designing process has the same multiple stages irrespective of the type of board and the layout, and it all begins with schematic captures.

Information about three key aspects of the project must be provided by the client to the designer. The schematic is obviously the most important thing. Note that it may also be in the netlist format. The netlist file contains the circuit's connectivity details and descriptions for the components.

Another thing the client is required to provide is the bill of materials (BOM) specifying each component used and its footprint. Designers are sometimes asked to help with component footprint capture. The client is also expected to provide the board outline. Once they have the schematic or netlist, BOM and the board outline, the designer should be able to do the rest.

There are many intermediate techniques used in several stages that build on the schematic or netlist. These functions include things such as library development, signal integrity checks, stress analysis, thermal simulation and EMI checking. All this leads up to the generation of the gerber file. This is the most commonly used format used for transferring complete PCB images ready for manufacturing.

The designer must be capable of coming up with solutions for complicated analog, digital, RF and mixed PCBs. Then there's also the type of board, which can be single-sided, double-sided or multi-layered. The board's size may vary, and so can the pin densities and component quantities.

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.

Components on boards that use this technology have their end caps soldered on the same side as the components themselves. This is hugely different from earlier techniques such as through-hole boards. The leads of components in such older boards were inserted through holes and soldered on to the traces on the other side.

Designing new boards is just one part of the services offered by PCB designers. They may also be asked to perform other functions such as evaluate designs, along with the components used and their footprints. Clients sometimes ask them to assist with procurement of prototypes and check for availability and pricing information against the BOM contents.

Certain PCB design services are required even after the client receives the finished product. Customers may seek changes to the design immediately or in future, and reorders are quite common. It works the other way around too, with designers asked to reverse engineer gerber files or film artwork into a netlist format or schematic. This is often required when complex circuits require heavy modifications at the most basic level.




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