gigAtec SA

Riot in component sizes

March 2024

It's no secret that components are getting smaller and smaller. And it's not just the transistors in microprocessors that are shrinking in size; passive components are also shrinking.

The standardization of package formats is managed by the JEDEC (Joint Electron Device Engineering Council) Solid State Association, part of the EIA (Electronic Industries Alliance), for both passive and active components.

Passive components :
Imperial and mil sizes, quite confusing!

Note that identical case size references exist in both imperial and metric, which can lead to confusion. It should be noted that imperial references are more widely used than metric ones, even though the USA officially converted to the metric system in 1975 under pressure from Jimmy Carter, with the adoption by the US Congress of the “Metric Conversion Act”.

Some of the most commonly used sizes:

Imperial ref Metric ref Size (mm)
0201 0603 0.60 x 0.30
0402 1005 1.00 x 0.50
0504 1210 1.20 x 1.00
0603 1608 1.60 x 0.80
0805 2012 2.00 x 1.25
1005 2512 2.50 x 1.20
1206 3216 3.20 x 1.60
1210 3225 3.20 x 2.50
1812 4532 4.50 x 3.20
2010 5025 5.00 x 2.50

MELF

MELF (Metal electrode leadless face) packages are generally used for diodes and resistors.

Transistors

The most common type of low-power transistor is the SOT (Small Outline Transistor), which comes in 3 sizes:

• The SOT-23 for low level signal transistors and measures 2.9 mm x 2.4 mm x 1.1 mm.

• The SOT-323 is used where space is limited and measure 2.1 mm x 2.1 mm x 0.9 mm.

• The SOT-523 is used where space is critical and measure 1.6 mm x 1.6 mm x 0.7 mm.

Integrated circuits

SOIC (Small Outline Integrated Circuit)
This SMD IC package has a dual in-line configuration and gull-wing leads with 1.27 mm pin spacing.

SOP – Small Outline Package
There are several versions of this SMD package with different pin spacings ranging from 0.4mm to 0.635mm:

    • • TSOP – Thin Small Outline Package

 

    • • SSOP – Shrink Small Outline Package

 

    • • TSSOP – Thin Shrink Small Outline Package

 

    • • QSOP – Quarter-size Small Outline Package

 

    • • VSOP – Very Small Outline Package

QFP- Quad Flat Pack
This box with tabs on all 4 sides allows a large number of interconnections.
There is several versions , metric or mil, plastic or ceramic, with or without protective corners, with or without heatsinks, etc.

QFN – Quad Flat No-lead
This box has no legs protruding from the box. This box generally has no more than 32 pins.

PLCC – Plastic Leaded Chip Carrier
This type of square case uses “J-lead” tabs with 1.27 mm spacing.

BGA – Ball Grid Array
This ball-matrix SMD package has all its contact points under the package. Before soldering, the pads appear as solder balls, hence their name.