|Name||SOIC (Small Outline Integrated Package)|
The SOIC family contains packages with a varying number of pins.
There are also two width's for SOIC packages, narrow width (3.9mm wide body, `SOICx_N`) and wide width (7.5mm wide body, `SOICx_W`). The width is usually expressed by the addition of `_N` or `_W` to the end of the package name. If the width is not mentioned, it is most likely going to be narrow width.
|Pin Count||8, 14, 16, 18, 20, 24, 28, 32|
|Solderability||Relatively easy to hand solder compared to other SMT packages.|
The dimensions for the
SOIC-8N package are shown below:
The dimensions for the
SOIC-16N component package are shown below:
SOIC packages have a pitch of 1.27mm (50mil) and usually have Gullwing leads. When used for regulators, sometimes the many ground pins are connected internally to the die attach flag, providing better heat sinking capabilities. SOIC packages use leadframe technology.
R-PDSO defined by JEDEC has a non-standard pitch of 0.65mm (and the standard wide body width of 7.5mm).
Pin numbering is the same as a
DIP package, in that pin 1 is at the top left, and then pins are numbered sequentially down the left-hand side, then up the right hand-side.
There are three ways of indicating the polarity on a
SOIC package. The first two, a dot or a notch, indicate pin 1 or the top of the chip. The third way is not so obvious, and features a bevelled edge along the side that pin 1 is on (so for
SOIC-8, the bevelled edge would be on the side with pins 1 to 4).
WSON package by SST is lower in height than a standard
SOIC package, but is designed to use the same PCB footprint.
Adapter PCBs for the
SOIC family of packages are widely available due to the popularity of the package.
SparkFun makes a
DIP-8-300 adapter PCB.
Thermal Resistance And Power Dissipation
This graph shows the maximum power dissipation for the
SOIC-8N component package, for various PCB copper areas.
Standard Pinout For MOSFETs
SOIC-8 component package is commonly used for medium-power N and P-channel MOSFETs. Most of these MOSFETs have the exact same pinout (both N and P-Channels!), as shown in the below diagram.
Note: As far I’m aware, this is not specified in any standard, but is just an industry default. Also, this only applies to
SOIC-8 packages with 1 MOSFET inside them.
SO-4 package is quite unique from other
SO packages. It typically has the same mechanical dimensions as a
SO-6 package, but has the two middle pins on either side removed. Typically the
SO-6 pin numbering is also kept, such that the remaining pins are numbered 1, 3, 4 and 6. Due to the large clearances between the pins and on the package, this
SO-4 package is used for optical isolators.
SO-4 package is different to the
SOIC-4 package, even though these two different names refer to the same package at higher pin counts.
ON Semiconductor uses the case code
751EP for the
- WSON Component Package
- DFN Component Package
- USON Component Package
- D2PAK Component Package
- DDPAK Component Package