Size comparison of transistor packages. Two surface-mount packages, SOT23 and SOT223, are shown next to through-hole packages
A small outline transistor (SOT) is a family of small footprint, discrete surface mount transistor commonly used in consumer electronics. The most common SOT are SOT23 variations,[1]. SOT23-5 differs from SOT23 in a wider body of 1.6 mm (0.063 in) instead of 1.3 mm (0.051 in). Also, manufacturers offer the nearly identical thin small outline transistor (TSOT/TSOP) package, where lower height is important.[2][3][4][5]
SOT23, SOT323, SOT416
The SOT23 package is very popular and a common package for transistors, as well as diodes and voltage regulators.[1]
SOT54 is an alternate designation for the JEDEC TO-92 package.[28]
SOT23-4, SOT143, SOT343
SOT23-4, SOT143 (TO253), SOT343
Dimensions (mm)
SOT143[29]
SOT343[30]
A
2.90 ±0.10
2.00 - 2.20
B
1.30 ±0.10
1.150 - 1.350
C
0.900 - 1.100
D
0.400 +0.110 -0.030
0.250 - 0.400
F
0.800 +0.130 -0.030
0.350 - 0.500
G
1.92 +0.11 -0.14
1.200 - 1.400
H
0.05 +0.05 -0.037
0.000 - 0.100
J
0.11 +0.07 -0.025
0.080 - 0.150
K
0.89 - 1.00
0.525
L
R
S
2.38 ±0.10
2.150 - 2.450
SOT490
SOT490 (SOT523F, SC89, EMT3F)
Dimensions (mm)
A
B
C
D
G
0.5
J
K
S
L
1.0
SOT89-3
The SOT89-3 electrically only has three leads (contact/pin). The wide lead (tab) is physically part of the middle lead on the other side of the package. Some call this package a SOT89-4, since it visually appears to have four leads when looking down at the part.
SOT89-3 (TO243AA, SC62, MPT3)[31]
Dimensions (mm)
A
4.5
B
2.5
C
1.5 ± 0.1
D
E
1.6
F
G
1.5
J
K
S
L
3
SOT89-5
The SOT89-5 electrically only has five leads (contact/pin). The middle lead is physically part of the middle lead on the other side of the package. Some call this package a SOT89-6, since it visually appears to have six leads when looking down at the part.
SOT89-5
Dimensions (mm)
A
4.6
B
2.6
C
1.6
D
E
F
G
1.5
H
J
K
S
L
SOT223 (SOT223-4)
The SOT223-4 package is a popular package for voltage regulators. It was introduced by Philips.[32]
SOT223-4 (SC73, TO261AA)[33][34][35]
Dimensions (mm)
Min
Typ
Max
A
1.80
A1
0.02
b
0.60
0.70
0.80
b2
2.90
3.00
3.10
c
0.24
0.26
0.32
D
6.30
6.50
6.70
e
2.3
e1
4.6
E
6.70
7.00
7.30
E1
3.30
3.50
3.70
SOT223-5
The SOT223-5 package is a popular package for voltage regulators.
SOT223-5[36]
Dimensions (mm)
Min
Typ
Max
A
1.8
A1
0.02
0.04
0.10
A2
1.55
1.65
A3
0.87
0.91
b
0.41
0.46
0.51
b2
2.95
3.00
3.05
C
0.24
0.32
D
6.45
6.50
6.55
E
6.86
7.00
7.26
E1
3.45
3.50
3.55
e
1.27
e1
5.08
L
0.91
1.14
SOT223-8
The SOT223-8 package is a popular package for bridged quad transistors.
^ abcde"SOT-23 and TSOT package datasheet" (PDF). Amkor Technology. 2021. Archived (PDF) from the original on December 19, 2018. Retrieved 2022-05-25. link from amkor.com/packaging/leadframe/sot23-tsot
^"Nexperia SOT 23 Package and Dimensions". SOT23 and SOT 23-3 with the smaller body are also known as TO-236AB.
^"SOT457 Package information" (PDF). NXP. 2018-05-05. Retrieved 2022-05-25. plastic, surface-mounted package (TSOP6); 6 leads; 0.95 mm pitch; 2.9 mm x 1.5 mm x 1 mm body
^"SOT363 Package information" (PDF). NXP. 2018-05-09. Retrieved 2021-09-07. plastic, surface-mounted package; 6 leads; 0.65 mm pitch; 2mm x 1.25 mm x 0.95 mm body
^Hollander, Dave (1995). "Packaging trends and mounting techniques for power surface mount components". Proceedings of 1995 International Conference on Power Electronics and Drive Systems. PEDS 95. Vol. 1. pp. 264–270. doi:10.1109/PEDS.1995.404911. ISBN 0-7803-2423-4. S2CID 109636238.
It is relatively common to find packages that contain other components than their designated ones, such as diodes or voltage regulators in transistor packages, etc.