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.

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.

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.

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.

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.

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.

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.