surfacemounted

Surfacemounted refers to electronic components and assemblies designed to be mounted directly onto the surface of printed circuit boards (PCBs) rather than inserted through holes. The term is commonly used to describe surface-mount technology (SMT) and the components built for it. In surface-mount assembly, components have terminations on their sides or bottom that attach to pads on the PCB, with electrical connections formed by solder, typically using reflow soldering. Mixed boards may also use wave soldering to attach any remaining through-hole parts.

Common surface-mounted components include resistors, capacitors, inductors, diodes, transistors, and integrated circuits, available in packages such as chip resistors, chip capacitors, small-outline and thin-chip packages, quad-flat packages, and more compact forms like QFN and BGA. The packaging is generally smaller and allows higher component density than through-hole alternatives.

Manufacturing typically involves solder paste printing on PCB pads, automated component placement with pick-and-place machines, and a reflow oven to melt solder and form joints. Inspection, testing, and, in some cases, X-ray analysis for complex joints are part of the process. Through-hole components may be used selectively on boards designed for mixed technology.

Advantages of surfacemanufacturing include higher component density, smaller and lighter boards, and compatibility with high-speed automated assembly, which can reduce cost per function. Disadvantages include greater sensitivity to thermal cycling, more challenging heat dissipation for high-power parts, and repair or rework being more difficult than with through-hole methods.

The term surfacemounted is often used interchangeably with surface-mount and SMD (surface-mount device) to describe components and practices within SMT.