Packaging types and identification of common SMT components

2022-08-04 107

Package type is a collection of external dimensions and shapes of components, and it is one of the important attributes of components. Components with the same electronic parameters may have different package types. Manufacturers produce components according to the corresponding packaging standards to ensure the assembly, use and special use of components. As the packaging technology is changing with each passing day and there is no unique standard for packaging code, this guide only gives the general packaging types and diagrams of electronic components, and the packaging unrelated to SMT process is not involved for the time being. Common SMT packages take the components used in the company's internal products as an example, as shown in the following table: Common SMT component packages are usually made of plastic and ceramic. The heat dissipation part of the component may be composed of metal. The pins of components are divided into lead and lead-free. SMT package graphic index Take the components used in the company's internal products as an example, as shown below: SMT package graphic index 1 strong > Meaning of common packages BGA(ball grid array): one of the surface mount packages with ball contact display. On the back of the printed substrate, spherical bumps are made to replace pins, and LSI chips are assembled on the front of the printed substrate, and then sealed by molding resin or potting. Also known as bump display carrier (PAC). 

The number of pins can exceed 200, which is a package for multi-pin LSI. The package body can also be made smaller than QFP (Four-sided Flat Package). For example, a 360-pin BGA with a pin center distance of 1.5mm is only 31mm square; While the 304-pin QFP with a pin center distance of 0.5mm is 40mm square. And BGA doesn't have to worry about pin deformation like QFP. This package was developed by Motorola, USA, and was first used in portable phones and other devices. Dil (dual in-line): another name for DIP (see Dip). European semiconductor manufacturers often use this name. DIP(dual in-line Package): the pins of dual in-line package are led out from both sides of the package, and the packaging materials are plastic and ceramic. DIP applications include standard logic IC, memory LSI, microcomputer circuit, etc. The pin spacing is 2.54mm, and the number of pins ranges from 6 to 64. Package width is usually 15.2mm .. Some packages with widths of 7.52mm and 10.16mm are called skinny DIP and slimDIP, respectively. But in most cases, there is no distinction, and it is simply called DIP. 

Flip-Chip: one of the packaging technologies of flip-chip bare chip, which makes metal bumps on the electrode area of LSI chip, and then connects the metal bumps with the electrode area on the printed substrate by pressure welding. The footprint of the package is basically the same as the chip size. It is the smallest and thinnest of all packaging technologies. However, if the thermal expansion coefficient of the substrate is different from that of LSI chip, there will be a reaction at the joint, which will affect the reliability of the connection. Therefore, resin must be used to reinforce LSI chips, and substrate materials with basically the same thermal expansion coefficient must be used. LCC(Leadless Chip carrier): A leadless chip carrier refers to a surface mount package in which the four sides of the ceramic substrate have only electrode contacts but no leads. It is a package for high-speed and high-frequency IC, also known as ceramic QFN or QFN-C (see QFN). PLCC(plastic leaded Chip carrier): Plastic chip carrier pins with leads are led out from four sides of the package, and are T-shaped. They are plastic products. Texas Instruments Company first adopted it in 64-bit DRAM and 256-bit RAM, and now it is widely used in logic LSI, DLD (or program logic device) and other circuits. The pin spacing is 1.27mm, and the number of pins ranges from 18 to 84. J-shaped pins are not easily deformed, which is easier to operate than QFP, but the appearance inspection after welding is more difficult. Plc is similar to LCC (also called QFN). In the past, the difference between the two is that the former uses plastic and the latter uses ceramic. But now there are J-shaped lead packages made of ceramic and leadless packages made of plastic (labeled plastic LCC, PCLP, P-LCC, etc.), which can't be distinguished. For this reason, Japan Electronic Machinery Industry Association decided in 1988 to call the package with J-shaped pins from four sides QFJ and the package with electrode bumps on four sides QFN (see QFJ and QFN).