PCB Blog - Summary of IC packaging principles and functional characteristics

This paper will introduce the packaging principles and functional characteristics of some commonly used ICs. By understanding the packaging of various types of ICs, electronic engineers can accurately select ICs when designing the principles of electronic circuits, and for factory batch production burning, they can quickly find the corresponding IC packaging burning seat model.

1. DIP dual in-line package

DIP refers to the integrated circuit chip packaged in dual in-line mode. Most small and medium-sized integrated circuits (ICs) adopt this packaging mode, and the number of pins is generally no more than 100. The IC packaged with DIP has two rows of pins, which need to be inserted into the chip socket with a DIP structure. Of course, it can also be directly inserted into the circuit board with the same number of solder holes and geometric arrangement for soldering. The DIP encapsulated chip shall be inserted and pulled out from the chip socket with special care to avoid damage to the pins.

DIP encapsulation has the following characteristics:

Suitable for punching and welding on PCB (printed circuit board), easy to operate;

The ratio between chip area and package area is large, so the volume is also large.

DIP is the most popular plug-in package, and its application scope includes standard logic IC, memory and microcomputer circuit.

2. QFP/PFP type encapsulation

The chip pins of QFP/PFP package are very small in distance and very thin. Generally, large-scale or ultra-large integrated circuits adopt this package form. The chip packaged in this form must be soldered to the motherboard using SMD (Surface Mount Device Technology). Chips installed with SMD do not need to be punched on the motherboard. Generally, there are designed solder joints of corresponding pins on the motherboard surface. Align the pins of the chip with the corresponding solder joints to realize the welding with the motherboard.QFP/PFP packaging has the following characteristics:

It is suitable for SMD surface mounting technology to install and wire on PCB Low cost, suitable for medium and low power consumption, and suitable for high-frequency use. Easy operation and high reliability. The ratio between chip area and package area is small. The mature sealing type can adopt traditional processing methods. At present, QFP/PFP packaging is widely used, and many MCU manufacturers' A chips adopt this packaging.

3.  BGA type encapsulation

With the development of integrated circuit technology, the packaging requirements for integrated circuits are more stringent. This is because the packaging technology is related to the functionality of the product. When the frequency of the IC exceeds 100MHz, the traditional packaging method may produce the so-called "CrossTalk" phenomenon, and when the number of IC pins is greater than 208 Pin, the traditional packaging method has its difficulties. Therefore, except for QFP packaging, most of today's high pin chips are converted to BGA (BALL Grid Array PACKAGE) packaging technology.

BGA packaging has the following characteristics:

Although the number of I/O pins has increased, the distance between the pins is far greater than that of QFP packaging, which improves the yield.  The contact surface between BGA array solder ball and substrate is large and short, which is conducive to heat dissipation. The pin of BGA array solder ball is very short, which shortens the signal transmission path, reduces the lead inductance and resistance; The signal transmission delay is small, and the adaptive frequency is greatly increased,so the circuit performance can be improved.  Coplanar welding can be used for assembly, which greatly improves the reliability.  BGA is suitable for MCM packaging and can achieve high density and high performance of MCM.

4. SO type encapsulation

The SO type package includes: SOP (small form factor package), TOSP (thin small form factor package), SSOP (reduced form factor SOP), VSOP (very small form factor package), SOIC (small form factor integrated circuit package) and other packages similar to the QFP form, but only a chip package with pins on both sides. This type of package is one of the surface mount packages. The pins are led out from both sides of the package in an "L" shape.The typical feature of this type of packaging is that many pins are made around the packaging chip. The packaging operation is convenient and the reliability is relatively high. It is one of the current mainstream packaging methods. At present, the common IC is applied to some memory types.

5.  QFN package type

QFN is a leadless quad flat package with peripheral terminal pads and a chip pad for mechanical and thermal integrity exposure.

The package can be square or rectangular. The four sides of the package are equipped with electrode contacts. Because there are no pins, the mounting area is smaller than QFP, and the height is lower than QFP.Features of QFN packaging. Surface mount package, no pin design.  The pin free pad design occupies a smaller PCB area.  The components are very thin (<1mm), which can meet the application with strict space requirements. Very low impedance and self inductance, which can meet high-speed or microwave applications;It has excellent thermal performance, mainly because there is a large area of heat dissipation pad at the bottom. Lightweight for portable applications.

QFN packaging features small shape, which can be used for portable consumer electronic products such as laptops, digital cameras, personal digital assistants (PDAs), mobile phones, and MP3. From the perspective of the market, QFN packaging is attracting more and more attention from users. Considering the cost and volume factors, QFN packaging will be a growth point in the next few years, with a very optimistic development prospect.

6.  PLCC package type

PLCC is a plastic chip packaging carrier with leads For surface mount packages, the pins are led out from the four sides of the package in a "T" shape, and the overall dimension is much smaller than that of DIP package. PLCC package is suitable for installing and wiring on PCB with SMT surface mounting technology and has the advantages of small size and high reliability.PLCC is a special pin chip package, which is a kind of chip package. The pins of this package bend inward at the bottom of the chip, so the chip pins cannot be seen in the top view of the chip. This kind of chip is welded by reflow process, which requires special welding equipment. It is also troublesome to remove the chip during debugging, and it is rarely used now.

As there are many types of IC packaging, it has little impact on R&D and testing, but for mass production and recording in factories, the more IC packaging types are, the more matching burner models will be selected; ZLG programmer, which has been specialized in chip burning industry for more than ten years, can support and provide burning seats with various types of IC packages for factory mass production.