As an electronic engineer, you will basically be exposed to many types of ICs in your daily work, such as logic chips, memory chips, MCUs or FPGAs, etc.; for the functional characteristics of various types of ICs, you may be more clear about them, but How much do you know about IC packaging? This article 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 electronic circuit principles, and for factory mass production and programming, they can more quickly Find the type of the programming socket corresponding to the IC package.
1. DIP dual in-line package
DIP refers to an integrated circuit chip packaged in a dual in-line format. Most small and medium-sized integrated circuits (IC) use this package format, and the number of pins generally does not exceed 100. The DIP packaged IC has two rows of pins, which need to be inserted into the chip socket with the DIP structure. Of course, it can also be directly inserted into a circuit board with the same number of solder holes and geometric arrangement for soldering. The DIP packaged chip should be especially careful when plugging and unplugging from the chip socket to avoid damaging the pins.
DIP package has the following characteristics:
1. Suitable for perforation welding on PCB (printed circuit board), easy to operate.
2. The ratio between the chip area and the package area is larger, so the volume is also larger.
DIP is the most popular plug-in package, and its application range includes standard logic IC, memory and microcomputer circuits, etc.!
2. QFP/ PFP type package
The QFP/PFP packaged chip has a small distance between the pins and the pins are very thin. Generally, large-scale or very large integrated circuits use this type of package. Chips packaged in this form must use SMD (Surface Mount Device Technology) to solder the chip to the motherboard. Chips mounted by SMD do not need to be punched on the motherboard. Generally, there are designed solder joints with corresponding pins on the surface of the motherboard. Align the pins of the chip with the corresponding solder joints to realize the soldering with the motherboard.
QFP/PFP package has the following characteristics:
1. Suitable for SMD surface mounting technology to install wiring on PCB circuit board;
2. Low cost, suitable for medium and low power consumption, suitable for high frequency use;
3. Convenient operation and high reliability;
4. The ratio between the chip area and the package area is small;
5. For mature sealing and turning types, traditional processing methods can be used.
At present, QFP/PFP packaging is widely used, and many MCU manufacturers' A chips use this packaging.
Three, BGA type package
With the development of integrated circuit technology, the packaging requirements for integrated circuits have become 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 difficulty. Therefore, in addition to the QFP packaging method, most of today's high-pin count chips are converted to BGA (BALL Grid Array PACKAGE) packaging technology.
The BGA package has the following characteristics:
1. Although the number of I/O pins has increased, the distance between the pins is much larger than the QFP packaging method, which improves the yield;
2. The contact surface between the BGA array solder ball and the substrate is large and short, which is good for heat dissipation;
3. The pins of the BGA array solder balls are very short, which shortens the signal transmission path and reduces the lead inductance and resistance; the signal transmission delay is small, and the adaptation frequency is greatly increased, thus improving the performance of the circuit;
4. Coplanar welding can be used for assembly, which greatly improves reliability;
5. BGA is suitable for MCM packaging and can realize the high density and high performance of MCM.
Four, SO type package
SO type packages include: SOP (small outline package), TOSP (thin small outline package), SSOP (reduced SOP), VSOP (very small outline package), SOIC (small outline integrated circuit package), etc. similar to QFP form The package is only a chip package with pins on both sides. This type of package is one of the surface mount packages, and the pins are drawn from both sides of the package in an "L" shape.
The typical feature of this type of package is that many pins are made around the packaged chip. The package is easy to operate and has high reliability. It is one of the current mainstream packaging methods. At present, it is more common to apply to some types of memory ICs.
Five, QFN package type
QFN is a leadless quad flat package, a lead-free package with peripheral terminal pads and a die 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 leads, the mounting area is smaller than QFP and the height is lower than QFP.
Features of QFN package:
1. Surface mount package, no lead design;
2. The leadless pad design occupies a smaller PCB area;
3. The components are very thin (<1mm), which can meet applications with strict requirements on space;
4. Very low impedance and self-inductance, which can meet high-speed or microwave applications;
5. It has excellent thermal performance, mainly because of the large area of heat dissipation pad at the bottom;
6. Light weight, suitable for portable applications.
The small form factor of the QFN package can be used in portable consumer electronic products such as notebook computers, digital cameras, personal digital assistants (PDAs), mobile phones and MP3. From a market perspective, QFN packaging is receiving more and more attention from users. Taking into account factors such as cost and volume, QFN packaging will be a growth point in the next few years, and its development prospects are extremely optimistic.
Six, PLCC package type
PLCC is a plastic chip package carrier with leads. It is a surface-mount package. The pins are drawn from the four sides of the package in a "T" shape, and the size is much smaller than that of the DIP package. The PLCC package is suitable for installing wiring on the 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 are bent inward at the bottom of the chip, so the chip pins are not visible in the top view of the chip. The soldering of this chip adopts a reflow soldering process, which requires special soldering equipment. It is also very troublesome to remove the chip during debugging, which is rarely used now.
