|Name||SOIC (Small Outline Integrated Package)|
|Variants||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 SMD packages.|
|Thermal Resistance||Depends on variant, see below.|
|Package LxWxH||Length and width depends on variant, height is usually between 1.50-2.54mm.|
|Typical PCB Land Area||Depends on variant, see below.|
There are are three different widths of SOIC packages, all which can be referred to as just SOIC by manufacturers in component datasheets! When designing a PCB, make sure to double-check the exact package width matches the PCB footprint/land pattern you’ve chosen.
- Package body width of 3.80mm (0.150"). JEDEC standard, commonly used for SOIC packages with a small pin count (16 or less).
- Package body width of 5.30mm (0.208"). EIAJ standard[^bib-dexpcb-soic], used for SOIC packages with higher pin counts (>16) or for isolated ICs (e.g. Maxim package
- Package body width of 7.52mm (0.300"). JEDEC standard, commonly called SOIC Wide or
SOIC-W(e.g. Maxim package
More on these different width SOIC packages below.
SOIC (JEDEC, 0.150" Package Body Width)
The JEDEC version of the
SOIC-xN (SOIC narrow)) family of packages is governed by the JEDEC MS-012-AA standard. There are non-exposed (normally just referred to as SOIC-x or SOIC-xN) and exposed pad versions (which are normally indicated with an “E” in the package name3).
The dimensions for the
SOIC-8N package are shown below:
The dimensions for the
SOIC-16N component package are shown below:
- SOIC-8: 29.4mm2
- SOIC-8: 70.6K/W (pads only, no copper fill)
- SOIC-8: 55K/W (6cm2 of copper, ground pins attached internally to die)
- SOIC-8: 33.5K/W (1 square inch of copper surrounding package, connected to ground)
SOIC (EIAJ, 0.208" Package Body Width)
Confusingly, the EIAJ standard defines a different body width of 5.3mm (0.208") for the `SOIC`` package, compared to the 3.8mm body width as defined in the JEDEC standard6. Generally used for ICs with a larger number of pins (>16).
SOIC-W (JEDEC, 0.300" Package Body Width)
SOIC-W (SOIC wide) family of packages is governed by the JEDEC MS-013 and IEC 075E03 standards. NXP’s
SOT-162-1 package is a SOIC-16W4.
|Package Name||Land Area|
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.
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
Retrieved 2021-12-08, from https://media.digikey.com/pdf/Data%20Sheets/Toshiba%20PDFs/TLP185_04-27-17.pdf. ↩︎
On Semiconductor (now onsemi) (2019, Sep). Bridge Rectifiers, 0.5 A: MB10S (datasheet). Retrieved 2022-03-08, from https://www.mouser.com/datasheet/2/308/1/MB10S_D-2314909.pdf. ↩︎ ↩︎
Monolithic Power Solutions (2012, May 30). MP2497-A: 3A, 50V, 100kHz Step-Down Converter with Programmable Output OVP Threshold. Retrieved 2022-01-20 from https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP2497A/document_id/1972. ↩︎ ↩︎
NXP (2016, Feb 8). SOT162-1: Plastic small outline package; 16 leads; body width 7.5 mm (package information). Retrieved 2022-01-25, from https://www.nxp.com/docs/en/package-information/SOT162-1.pdf. ↩︎ ↩︎ ↩︎
Retrieved 2021-12-08, from https://nz.mouser.com/datasheet/2/308/1/FODM1009_D-2313636.pdf. ↩︎
This work is licensed under a Creative Commons Attribution 4.0 International License .
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