SOT-223 Component Package

Overview

Name SOT-223 (Small-outline Transistor 223)
Synonyms
  • DCQ (SOT-223-5, Texas Instruments)
  • DCY (SOT-223, Texas Instruments)
  • MP04A (National Semiconductor)
  • PG-SOT-223-4 (Infineon Technologies)
  • R-PDSO-G6 (SOT-223-5, Texas Instruments)
  • ST Package (Analog Devices)
  • TO-261-4
Variants
  • SOT-223-3 (3 pin excl. tab)
  • SOT-223-4 (4 pin excl. tab)
  • SOT-223-5 (5 pin excl. tab)
Similar To
Mounting SMD
Pin Count 3, 4, 5 (excl. tab)
Pitch n/a
Solderability Easily solderable by hand
Thermal Resistance

SOT-223-3

  • \(T_{JA} = 174^{\circ}{\rm C}/W\) (standard footprint)
  • \(T_{JA} = 75^{\circ}{\rm C}/W\) (\(300mm^2\) heatsink area)
  • \(T_{JA} = 63^{\circ}{\rm C}/W\)(\(600mm^2\) heatsink area)
  • \(T_{JA} = 27^{\circ}{\rm C}/W\)(one square inch copper fill surrounding package)

SOT-223-5

  • \(55-165^{\circ}{\rm C}/W\) (see the SOT-223-5 section below)

 

Dimensions n/a
3D Models n/a
Common Uses
  • MOSFET’s
  • Load switches
  • High-power linear regulators
  • Current sources

Conflicting Naming Conventions

WARNING: Some manufacturers use the term SOT-223-3 to refer to the 3-pin, 1 -tab package, while others count the tab as a “pin”, and so name it SOT-223-4. However this conflicts with the first lot of manufacturers who use the term SOT-223-4 to refer to the package with 4 pins and 1 tab. In summary, BE CAREFUL.

This page associates the x in SOT-223-x to stand for the number of pins excluding the tab. This is the most popular convention.

SOT-223-3

The SOT-223-3 (TO-261AA) component package is the most common variant within the SOT-223 family. It looks similar to the SOT-23 package, but with a tab on one side instead of legs.

A 3D render of the TO-261AA (SOT-223) component package.
A 3D render of the TO-261AA (SOT-223-3) component package.

It is commonly used for medium-power linear regulators and load switches.

Thermal Resistance

Texas Instruments gives the following thermal resistance data for the SOT-223-3 package (taken from here).

Property Symbol Value
Junction-to-ambient thermal resistance \(R_{\theta JA}\) \(64.2^{\circ}C/W\)
Junction-to-case (top) thermal resistance \(R_{\theta JC(top)}\) \(46.8^{\circ}C/W\)
Junction-to-board thermal resistance \(R_{\theta JB}\) \(13.3^{\circ}C/W\)
Junction-to-top characterisation parameter \(R_{\psi JT}\) \(6.3^{\circ}C/W\)
Junction-to-board characterisation parameter \(R_{\psi JB}\) \(13.2^{\circ}C/W\)
All of the parameters in the above table were measured with the SOT-223-3 package soldered to a JEDEC standard high-K profile, JESD 51-7, 2s2p four layer board with 2-oz copper. The copper pad was soldered to the thermal land pattern.
The thermal resistance of the TO-261AA (SOT-223) component package for various PCB footprints.
The thermal resistance of the TO-261AA (SOT-223-3) component package for various PCB footprints.

 

Standard Linear Regulator Pinout

The SOT-223-3 package is commonly used for small, medium-power linear regulators. There is a de-facto standard pinout that many manufacturers use when incorporating a linear regulator into the SOT-223-3 package:

The de-facto standard pinout for a linear regulator inside a SOT-223-3 package. This image also shows the standard PCB footprint used to achieve a low thermal resistance. Image from http://www.ti.com/.
The de-facto standard pinout for a linear regulator inside a SOT-223-3 package. This image also shows the standard PCB footprint used to achieve a low thermal resistance. Image from http://www.ti.com/.

Standard Load Switch Pinout

The SOT-223-3 package is commonly used for smaller low and high-side load switches. As such, there is a de-facto standard pinout that many manufacturers use for load switches in the SOT-223-3 package:

The de-facto standard pinout for a load switch in a SOT-223-3 package. Image from http://www.infineon.com/.
The de-facto standard pinout for a load switch in a SOT-223-3 package. Image from http://www.infineon.com/.

SOT-223-4

This variant can be confused with the three pin and one pad variant (SOT-223-3) if you decide to count the pad as well as the pins in the number.

A 3D render of the SOT-223-4 component package. Image from http://www.datasheetdir.com/.
A 3D render of the SOT-223-4 component package. Image from http://www.datasheetdir.com/.

SOT-223-5

Dimensions

Below are the dimensions of the SOT-223-5 package as specified by Texas Instruments.

The dimensions of the SOT-223-5 component package. Image from http://www.ti.com/.
The dimensions of the SOT-223-5 component package. Image from http://www.ti.com/.

Footprint (Land Pattern)

Below is the recommended footprint (land pattern) for the SOT-223-5 component package as specified by Texas Instruments.

A recommended footprint (land pattern) for the SOT-223-5 component package. Image from http://www.ti.com/.
A recommended footprint (land pattern) for the SOT-223-5 component package. Image from http://www.ti.com/.

Thermal Resistance

Below is a graph showing the thermal resistance of the SOT-223-5 package with varying copper area.

Graph of thermal resistance vs. copper area for the SOT-223-5 component package. Image from http://www.ti.com/.
Graph of thermal resistance vs. copper area for the SOT-223-5 component package. Image from http://www.ti.com/.

As you can see, as the copper area increases, the thermal resistance decreases asymptotically to around \(55^{\circ}{\rm C}/W\).

Posted: January 8th, 2015 at 3:04 pm
Last Updated on: April 14th, 2016 at 2:55 pm