What is IC Packaging?
The final step in manufacturing a semiconductor device is integrated circuit packaging, which involves encasing the semiconductor material block (from which a functional circuit is made) in a protective case to protect it from physical damage and corrosion. There are many types of IC packages, each with unique dimensions, mounting styles, and pin counts.
IC Package Types
The most common IC package types include-
- DIP IC Package
2. SMD IC Package
- QFP -> TQFP, VQFP, LQFP
- SOP -> PSOP, TSOP, TSSOP
- SOT IC Package
3. SOIC Package
4. BGA IC Package
5. QFN IC Package
Dual-in-line Package (DIP)
This is the most common through-hole IC package used in circuits, especially hobby projects. This IC has two parallel rows of pins extending perpendicularly from a rectangular plastic housing.
The overall size of a DIP package depends on its pin count. The most common pin counts are four, six, eight, fourteen, eighteen, twenty, twenty-eight, and forty pins. The pins of a DIP IC are spaced 2.54mm apart, which is a standard spacing, perfect for inserting breadboards, veroboards, and other prototyping boards.
A DIP IC can also be easily soldered onto PCBs. Sometimes, an IC socket is used instead of soldering an IC directly to the PCB. Using a socket allows the DIP IC to be removed and inserted into the PCB easily.
Surface-mount Device (SMD)
There are various surface mount packages including SOP, small outline transistor (SOT), and QFP available in the market. SMD IC packages often require custom PCBs, which have a matching copper standard to which they are soldered. Usually, special automated tools are used to solder them to PCBs.
Small outline IC (SOIC)
The SOIC package is shorter and narrower than the DIP. It is an SMD with all the DIP pins bent outward and reduced in size. Each pin is usually spaced about 1.27mm from the next.
Small Outline Package (SOP)
This is a smaller version of the SOIC package. Like SOIC, the SOP family has a smaller form factor, with a pin spacing of less than 1.27mm. Each SOP includes plastic small-outline package (PSOP), thin small-outline package (TSOP), and thin-shrink small-outline package (TSSOP).
Quad-flat Package (QFP)
Unlike DIP which has two sides, QFP IC has pins on all four sides. A QFP IC can have anywhere from eight pins per side (32 total) to upwards of seventy (300+). The pins on a QFP IC are typically spaced anywhere from 0.4mm to 1mm apart.
Small variants of the standard QFP package include thin QFP (TQFP), very-thin QFP (VQFP), and low-profile QFP (LQFP) packages.
Quad-flat no-leads (QFN)
There is another type of QFP IC, but with a different pin structure, called the QFN package. The pins of a QFN package are exposed on the bottom and sometimes on both sides and bottom.
Small Outline Transistor (SOT)
SMD devices such as rectangular transistors are available in SOT packages.
Ball-grid Array (BGA)
Advanced ICs are available in BGA packages. These incredibly intricate packages have tiny balls of solder arranged in a 2D grid on the bottom. Typically, placing these packages on a PCB requires an automated process involving pick and place machines and reflow ovens. BGA packages can be found on pcDuino and Raspberry Pi boards.