PCB Pad-What Is It and How To Use It
Printed circuit boards are composed of many components such as the base or insulation, copper layer, copper traces for inter-connection of components, holes to hold the components, silk screen to represent marking on the surface.PCB pad to provide the solid metal surface for holding components with the help of solder and solder masking layer to protect the routes etc.
2.Types of PCB pads
PCB pad are typically round in shape or they can be rectangular as shown in figure below. The footprint for a component on surface of printed circuit board decides the shape of the PCB pad.
2.Types of PCB pads
There are two types of PCB pads in the market of printed circuit boards. One type is use in surface mount technology and other type is through-hole technology.
With the advancement in the printed circuit board technology, surface mount technology become popular. This technology places the components on the surface of printed circuit board with the help of robotic machines. The other robotic machines interconnect these components by soldering them to the surface of printed circuit board. These PCB pads provide mechanical support to the component that holds solder joint of component with the portion of copper beneath it.
The other type is through-hole technology which have PCB pads of exposed copper on the surface of printed circuit board with holes in them to hold the legs of components. These components are again soldered on the surface of PCB using these PCB pads.
The two terms are often confused with each other. One is PCB pad and other is via hole. The main difference between PCB pad and via hole is that PCB pad exists on the surface of printed circuit board while via-hole passes from the layers of printed circuit board.
PCB pad is specified in the ring with two parameters. First parameter is drill size of hole in the center of a circular pad as shown in figure below and other parameter is diameter of annular ring or the size of sides in case of a rectangular PCB pad.