|Name||SOT-23 (Small Outline Transistor 23)|
|Variants||There are 3-pin (SOT-23-3), 5-pin (SOT-23-5), 6-pin (SOT-23-6) and 8-pin (SOT-23-8) variants.|
|Pin Count||3, 5, 6, 8|
|Solderability||Easy to hand-solder if you have had a bit of practise with surface mount devices before. Easy to solder with infrared or reflow techniques.|
|Dimensions||The body of all SOT-23-x packages is 1.30x2.92mm. Component Area = 7.98mm² (2.9x2.75mm) Standard Footprint Land Area = 11.22mm² (3.3x3.4mm)|
SOT-23 is a very common surface-mount package that is used for a huge number of functions. Variations exist with 3 to 8 pins. When surface mount components were just beginning to gain popularity,
SOT-23 was introduced to replace the well used through-hole 3-pin TO-18 and TO-92 transistor packages, and so the first variant of SOT-23 was the 3 leaded version (SOT-23-3, officially called TO-236AA by JEDEC).
The SOT-23 family probably has the largest number of differing variant names which all refer to the same packages (see the synonym section above).
The number of pins used not only depends on the required number of connections but also the desired thermal resistance (high-current SOT23 devices may use more than one pin for the same net to improve thermal performance). Used commonly for FETs transistors, diodes, and other components only having a small number of leads. SparkFun makes a SOT-23 to DIP breakout board.
The 3, 5, and 6 pin SOT-23 variants have the same pitch of 0.95mm, and all are compatible with the 6 pin footprint (which means you can use a SOT-23-6 adapter board for the 3 and 5 pin variants also).
JEDEC formalized the dimensions of the SOT-23 package (and all it’s variants) in the MO-178 document (with package designator
R-PDSO-G). After registering, you can download this document for free from (
What Is The Difference Between TO-236AA And TO-236AB?
TO-236AB are official JEDEC names for the SOT-23-3 package. An image comment on Wikipedia1 states that the
TO-236AB package is approximately 0.1mm higher. However it is hard to verify this claim by comparing manufacturer package dimensions, as 0.1mm is well with the manufacturing tolerances.
SOT-23-6 has a pitch of 0.95mm.
Also called SOT-753 or SC-74A.
SOT-23-6 has a pitch of 0.95mm. Also called SC-74.
Non-standard Pin Numbering
Why you’d ever number the package in that manner is beyond me. It’s dangerous, and bound to cause PCB designers to do board respins!
SOT-23-8has a smaller pitch of 0.65mm compared to the
SOT-23-6which all have a pitch of 0.95mm. This is to fit the 4 pins on each side, the original
SOT-23design (which is a synonym for
SOT-23-3) only had room for a maximum of 3 pins per side.
This work is licensed under a Creative Commons Attribution 4.0 International License .
- SOT-457 Component Package
- SC-59 Component Package
- TO-236AA Component Package
- TO-236AB Component Package
- SMT3 Component Package
- component packages
- PCB design
- Analog Devices