SOT-23 Component Package

Overview

Name SOT-23 (Small Outline Transistor 23)
Synonyms

SOT-23-3

  • Micro3
  • SC-59 (JEITA)
  • SOT-23 (TopLine)
  • SOT-346
  • SSOT3 (Fairchild Semiconductor)
  • TO-236AA (JEDEC)
  • TO-236AB (NXP)

SOT-23-5

  • SC-74A (JEITA)
  • SOT-753
  • SOT-25 (TopLine)

SOT-23-6

  • SC-74 (JEITA)
  • SMT6 (ROhm)
  • SOT-26 (SOT-23-6 by TopLine)
  • SOT-457 (JEDEC)

SOT-23-8

  • RJ-8 (Analog Devices)
  • SM8 (Diodes Incorporated)
  • SOT-28 (TopLine)
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.
Similar To n/a
Mounting SMD
Pin Count 3, 5, 6, 8
Pitch
  • 0.65mm (SOT-23-8)
  • 0.95mm (SOT-23-3, SOT-23-5, SOT-23-6)
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 1.30×2.92mm.
3D Models n/a
Common Uses
  • Linear regulators
  • Op-amps
  • Transistors
  • MOSFET’s
  • Diodes (including diode arrays)
  • Battery management IC’s
  • Analogue active linear temperature sensors

Comments

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.

A 3D render of the SOT-23 component package.
A 3D render of the SOT-23 component package.

 

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.

A 3D render of the SOT-23-6 (SOT-457) component package.
A 3D render of the SOT-23-6 (SOT-457) component package.

 

Dimensions

Dimensions for the SOT-23-8 component package. Image from http://www.diodes.com/.
Dimensions for the SOT-23-8 component package. Image from http://www.diodes.com/.

Footprint

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

A recommended footprint for the SOT-23-8 component package. Image from http://www.diodes.com/.
A recommended footprint for the SOT-23-8 component package. Image from http://www.diodes.com/.

SOT-23-6

Non-standard Pin Numbering

WARNING: The SOT-23-6 package by Rohm (a.k.a IMT4, SOT-457, SMT6) has non-standard, clockwise pin numbering starting at the top right pin.

The Rohm SOT-23-6 component package (a.k.a. SOT-457, IMT4) with non-standard pin numbering.
The Rohm SOT-23-6 component package (a.k.a. SOT-457, IMT4) with 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!

Other Images

package-dimensions-sot23-3 The dimensions of the SOT-23-5 component package.