Printed circuit boards are the basic building blocks for many electronic devices. They are composed of copper tracks and traces that allow signals to travel between electrical components on the board. The copper tracks and traces are often connected to one another by metal that is used as an adhesive.
The process of making a pcb is a multi-step procedure that involves schematic creation and simulation, setting up PCB design grids and DRCs, component placement, routing, power planes, and final assembly. All of these processes work in concert to produce a high-quality, robust circuit that delivers the required performance.
Schematic Capture
Getting your circuit diagram into the right format for PCB layout is an important step in the entire process. This is achieved by using a circuit board design software that allows you to transfer your schematic information into a blank PCB layout. In Altium Designer, for example, you can easily capture the information you want to transfer by using a special tool in the software called Schematic Capture.
After you have your circuit schematic in the correct format for the layout, it is time to create the actual PCB layout. CAD software can be helpful here, as it will have many features to help you organize the layout and connect the nets together.
Component Placement
After the layout is completed, it is time to put the components in their optimal positions. In order to do this, the layout designer will need to know the smallest dimensions of each component and where it needs to be placed on the board. Using a component overlay diagram in a layout software package, the designer will be able to determine where each component needs to be placed on the board.
Once the parts are in their appropriate places, it is time to connect the nets together with traces and planes. This is a critical part of the entire design process because it requires great care to ensure that the nets are not over-connected or too long for the signals they are carrying. Moreover, these connections need to be routed in such a way that they don’t interfere with each other or cross over areas of excessive noise.
The routing process is very similar to the layout process, although it is slightly more complex. In the routing step, the layout designer will convert the rubber-band net connections into drawn traces and planes that connect each component pin to the others.
Routing is essential for PCB fabrication because it ensures that the wires and traces don’t interfere with each other. This prevents signal integrity problems that could degrade the performance of the board and affect its functionality.
Typically, the routing is done by hand, but it can be automated as well. Several CAD tools have features that automate this process, saving the designer ample time.
With all the components arranged, it’s time to add the labels and reference designators. These symbols, usually printed on the board, will be visible during assembly and testing of the circuit. They can also be used to assist in debugging the device.