Small-outline integrated circuit

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A small-outline integrated circuit (SOIC) is an integrated circuit (IC) package which occupies an area about 30 - 50% less than an equivalent DIP, with a typical thickness that is 70% less. They are generally available in the same pinouts as their counterpart DIP ICs. The convention for naming the package is 'SOIC' or sometimes just 'SO' followed by the number of pins. For example, a 14-pin 4011 would be housed in an SOIC-14 or SO-14 package.

[edit] General package characteristics

This package is shorter and narrower than DIPs, the side-to-side pitch being 6 mm for an SOIC-14 (from lead tip to lead tip) and the body width being 3.9 mm. These dimensions differ depending on the SOIC in question, and there are several variants. This package has "gull wing" leads protruding from the two long sides and a lead spacing of 0.050 inches.

The picture below shows the general shape of an SOIC, with major dimensions. The values of these dimensions (in mm) for common SOICs is shown in the table.

A general SOIC, with major dimensions.
 
 C  Clearance between IC body and PCB
 H  Total Carrier Height
 T  Lead Thickness
 L  Total Carrier Length 
 LW Lead Width
 LL Lead Length
 P  Pitch
 WB IC Body Width
 WL Lead-to-Lead Width
 O  End Overhang
Package WB WL H C L P LL T LW O
SOIC-8 4.0 (3.8) 6.2 (5.8) 1.75 0.25 (0.10) 5.0 (4.8) 1.27 .41 (1.04) .19 (.25) .51 (.33) .33
SOIC-14 3.9 5.8-6.2 1.72 0.10-0.25 8.55-8.75 1.27 1.05 0.19-0.25 0.39-0.46 0.3-0.7
SOIC-16 3.9 5.8-6.2 1.72 0.10-0.25 9.9-10 1.27 1.05 0.19-0.25 0.39-0.46 0.3-0.7
SOIC-16 7.5 10.00-10.65 2.65 0.10-0.30 10.1-10.5 1.27 1.4 0.23-0.32 0.38-0.40 0.4-0.9

[edit] SOP

After SOIC came a family of smaller form factors, Small Outline Package (SOP), with a pin spacing of 0.65 mm:

  • Plastic Small-Outline Package (PSOP)
  • Thin Small-Outline Package (TSOP)
  • Shrink Small-Outline Package (SSOP)
  • Thin-Shrink Small Outline Package (TSSOP)

The ICs on DRAM memory modules were usually TSOPs until they were replaced by ball grid array (BGA).

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