Sunday 22 December 2013

PCB Design Services For The Electronics Industry

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.

Starting from the netlist/schematic, the process is taken further using techniques including library development, signal integrity and EMI checks, stress analysis, thermal simulation, etc. The series of intermediate steps ends with the creation of the gerber file. This format is the preferred one used by the electronics industry to transfer finished PCB images that are ready to be used in the manufacturing stage.

Electrical and electronics circuit designers are expected to be able to work with and create complex designs for digital, analog, RF and mixed PCBs. The boards themselves may be single or double sided or multi-layered. They can be designed to match the customer's needs in different sizes with varying pin densities and component quantities.

Another important thing that has to be decided in the designing stage is about the characteristics of the board. The most critical thing is deciding the technique used for creating traces and mounting components. The most widely used solution is 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.

In addition to designing new boards, PCB designers are often called upon to perform other tasks. For instance, one common service is an evaluation of an existing design, its components and the footprint captures. They may also be asked to help out with procuring prototypes, check for availability and price information against the bill of materials.

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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