|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.|
|Thermal Resistance||SOT-23-5: 230°C/W|
|Dimensions||The body of all SOT-23-x packages is 1.30x2.92mm.|
A very common surface-mount package that is used for a huge number of functions. Variations exist with 3 to 8 pins.
The SOT-23 family probably has the largest number of differing variant names which all refer to the same packages.
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 FET’s 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).
However, the 8 lead variant, SOT-23-8, has a smaller pitch of 0.65mm
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!