SOT-23 COMPONENT PACKAGE

SOT-23 Component Package

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Date Published:	April 6, 2015
Last Modified:	January 15, 2020

Overview

Name	SOT-23 (Small Outline Transistor 23)
Synonyms	SOT-23-3 Micro3 (Infineon, International Rectifier) MPAK (NXP Semiconductors) RJ-3 (Analog Devices) SC-59 (JEITA/EIAJ) SC-59A (JEITA/EIAJ) SMT3 (NXP Semiconductors, ROHM Semiconductor) SOT-23 (if no additional number is provided, assume SOT-23 has 3 pins) SOT-346 SSOT3 (Fairchild Semiconductor) TO-236AA (JEDEC) TO-236AB (JEDEC) SOT-23-5 RJ-5 (Analog Devices) SC-74A (JEITA) SOT-753 SOT-25 (TopLine) SOT-23-6 RJ-6 (Analog Devices) 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) `R-PDSO-G` is the JEDEC package designator for SOT-23 in all it’s variants[^jedec-mo-178-c].
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	0.95mm (SOT-23-3, SOT-23-5, SOT-23-6) 0.65mm (SOT-23-8)
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-23-3: 500°C/W SOT-23-5: 230°C/W
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)
3D Models	n/a
Common Uses	Linear regulators Op-amps Transistors MOSFETs Diodes (including diode arrays) Battery management ICs Analogue active linear temperature sensors

Comments

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).

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 FETs 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.

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 (https://www.jedec.org/standards-documents/docs/mo-178-c)[https://www.jedec.org/standards-documents/docs/mo-178-c].

The SOT-23F package is closely related to the SOT-23 put has flat leads instead of gull-wing leads.

What Is The Difference Between TO-236AA And TO-236AB?

Both TO-236AA and 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-23-3

The SOT-23-6 has a pitch of 0.95mm.

Dimensions

SOT-23-5

Also called SOT-753 or SC-74A.

SOT-23-6

The SOT-23-6 has a pitch of 0.95mm. Also called SC-74.

Non-standard Pin Numbering

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.

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-23-8

Dimensions

Recommended Footprint

The SOT-23-8 has a smaller pitch of 0.65mm compared to the SOT-23-3, SOT-23-5, and SOT-23-6 which all have a pitch of 0.95mm. This is to fit the 4 pins on each side, the original SOT-23 design (which is a synonym for SOT-23-3) only had room for a maximum of 3 pins per side.