Surface mount technology, SMT includes:
What is BGA, what is BGA, SMD, SMT component packaging: dimensions, dimensions, details, what is BGA, and what is BGA like
Now look at any commercial electronic device, it is filled with tiny devices. These components are installed on the surface of the board, rather than using traditional components with leads, such as wire leads that can be used in home buildings and kits, and many components have very small dimensions.
This technology is called surface mount technology, SMT, and SMT components. Almost all Almost all’s equipment uses SMT commercially, because it provides significant advantages in the manufacturing process, and considering the size, the use of SMT components enables more electronic components to be packaged into smaller spaces.
In addition to size, surface mount technology can also use automated production and welding, significantly improving reliability.
Typical PCB using surface mount technology
What is SMT?
In the 1970s and 1980s, the automation level of electronic equipment construction began to improve. The use of traditional components and leads is not easy. Resistors and capacitors need to pre form their leads to fit through holes, and even require integrated circuits to set their leads to the correct spacing so that they can easily pass through holes.
For printed circuit board technology, there is no need for component leads to pass through the circuit board. On the contrary, soldering components directly onto the circuit board is sufficient. Therefore, surface mount technology (SMT) has emerged, and the use of SMT components has rapidly developed due to their advantages being realized and realized.
Concept of Surface Mount Technology: Typical Passive Components
Today, surface mount technology is the main technology used in electronic manufacturing. SMT components can be manufactured very small and can use billions of types, especially capacitors and resistors.
SMT equipment
Surface mount technology, SMT, components or surface mount devices, SMD, as they are often referred to as different from their lead containing counterparts. SMT components are designed for wiring between two points, rather than being placed and soldered onto the circuit board. They result in not passing through the holes on the circuit board like traditional lead containing components. There are different types of packages for different types of components. Broadly speaking, packaging types can be divided into three categories: passive components, transistors and diodes, and integrated circuits. These three types of SMT components are shown below.
A series of surface mount technology components
Passive SMD: There are many types of packaging used for passive SMD. However, most passive SMDs are resistors or capacitors, and their packaging dimensions are reasonably standardized. Other components, including coils, crystals, and other components, often have more personalized needs, hence their own packaging.
Resistors and capacitors come in various packaging sizes. Their names include: 18121206080506030402 and 0201. These figures refer to dimensions in the hundreds of inches. In other words, the dimensions of 1206 range from 12 to 6 hundred inches. Larger sizes such as 1812 and 1206 were the first to be used. They are not widely used now because smaller components are usually required. However, they can be used in applications that require higher power levels or other considerations that require larger sizes.
The connection with the printed circuit board is carried out through the metallized areas at both ends of the package.
Transistors and diodes: These components are usually contained in a small plastic package. The connection is emitted from the package through leads and bent so that they come into contact with the circuit board. These packages always use three leads. In this way, it is easy to identify which path the device must take.
Integrated Circuit: There are various types of packaging used for integrated circuits. The packaging used depends on the level of interconnection required. Many chips such as simple logic chips may only require 14 or 16 pins, while others such as VLSI processors and related chips require up to 200 or more. Given the widespread changes in requirements, many different packages can be used.
For smaller chips, packaging such as SOIC (Small Form Factor Integrated Circuit) can be used. These are SMT versions of the familiar DIL (Dual Inline) packaging for familiar 74 series logic chips. In addition, there are smaller versions, including TSOP (Thin Small Form Factor Package) and SSOP (Shrink Small Form Factor Package).
VLSI chips require different methods. Usually, packaging called square flat packaging is used. It has square or rectangular footprints and pins on all four sides. Bend the pins again from the packaging into the so-called gull wing shape so that they meet the board. The spacing between pins depends on the number of pins required. For certain chips, it may be close to two thousandths of an inch. When packaging these chips and handling them, great care needs to be taken as the pins are easily bent.
Other packages are also available. A type called BGA (Ball Grid Array) is used in many applications. They are located below, rather than having connections on the side of the packaging. The connecting pad has solder balls that melt during the welding process, making it well connected and mechanically connected to the circuit board. Due to the ability to use the entire lower side of the package, the spacing between connections is wider and more reliable.
Smaller versions of BGA (called microBGA) are also used for certain ICs. As the name suggests, it is a smaller version of BGA.
SMT in use
Nowadays, SMT is almost exclusively used for manufacturing electronic circuit boards. They are smaller, typically providing a better level of performance, and can be used in conjunction with automatic pickup and placement machines, all of which in many cases eliminate the need for manual intervention during the assembly process.
Wired components are always difficult to automatically place because they require pre formed wires to adapt to the relevant hole spacing, and even so, they are prone to placement issues.
Although many connectors and some other components still require auxiliary placement, printed circuit boards are usually developed to reduce them to absolute minimum values, and even design changes are made to use components that can be automatically placed. In addition, component manufacturers have also developed specialized surface mount versions of components that can almost complete the automated assembly of most circuit boards.
SMT application
Although some SMT components can be used in home buildings, great care needs to be taken when welding. Additionally, even ICs with wide pin spacing may be difficult to solder. Without special equipment, pins with fifty or more pins cannot be soldered. They are only used for large-scale manufacturing. Even working on already built circuit boards requires great care. However, these SMT components have saved manufacturers a lot of costs, which is why they were adopted. Fortunately, for home construction, traditional lead components that can be manually welded can still be widely used and provide better solutions for home buildings.
