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Briefly speaking, the LED die is assembled face down on the sub-mount, which is usually silicon or ceramic, acting as the heat spreader and supporting substrate. The flip-chip joint can be eutectic, high-lead, lead-free solder or gold stub. The primary source of light comes from the back side of the LED chip, and there is usually a built-in ...
Solder makes a strong electrical and mechanical connection. Point-to-point wiring is not suitable for automated assembly (though see wire wrap , a similar method that is) and is carried out manually, making it both more expensive and more susceptible to wiring errors than PCBs, as connections are determined by the person doing assembly rather ...
Surface-mount technology (SMT), originally called planar mounting, [1] is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). [2] An electrical component mounted in this manner is referred to as a surface-mount device ( SMD ).
Dip soldering is used for both through-hole printed circuit assemblies, and surface mount. It is one of the cheapest methods to solder and is extensively used in the small scale industries of developing countries . Dip soldering is a manual equivalent of automated wave soldering. The apparatus required is just a small tank containing molten solder.
Solder paste is used in the manufacture of printed circuit boards to connect surface mount components to pads on the board. It is also possible to solder through-hole pin in paste components by printing solder paste in and over the holes. The sticky paste temporarily holds components in place; the board is then heated, melting the paste and ...
The solder is usually a mixture of metals. A typical leaded solder is composed of 50% tin, 49.5% lead, and 0.5% antimony. [1] The Restriction of Hazardous Substances Directive (RoHS) has led to an ongoing transition away from 'traditional' leaded solder in modern manufacturing in favor of lead-free alternatives. Both tin-silver-copper and tin ...
From the 1980s onward, small surface mount parts have been used increasingly instead of through-hole components; this has led to smaller boards for a given functionality and lower production costs, but with some additional difficulty in servicing faulty boards. In the 1990s the use of multilayer surface boards became more frequent.
Flat no-leads, also known as micro leadframe (MLF) and SON (small-outline no leads), is a surface-mount technology, one of several package technologies that connect ICs to the surfaces of PCBs without through-holes. Flat no-lead is a near chip scale plastic encapsulated package made with a planar copper lead frame substrate.