SOT223 Package Overview

The SOT223 (Small Outline Transistor 223) is a medium-power    surface-mount package that bridges the gap between the small-signal SOT-23 and    the larger DPAK (TO-252). It is standardized as TO-261 under    JEDEC and SC-73 under Pro Electron.

Key Features

  • Compact size: ~6.5 mm × 3.5 mm body, 1.6–1.8 mm height, 2.3 mm pin pitch.
  • Thermal performance: θJA ≈ 100 °C/W; power dissipation of 1–2 W with adequate copper.
  • Current capability: Up to ~1–2 A continuous with proper PCB heat sinking.
  • Easy hand soldering: Large pads and tab make it one of the most hand-solder-friendly SMD packages.
  • DPAK drop-in replacement: Pin-compatible with DPAK footprint; only 2–3 °C higher temperature rise.

Pin Configuration

SOT223 typically has 3 or 4 gull-wing leads on one side and a large central    metal tab on the opposite side for both electrical connection and heat    dissipation. Pin functions vary by device type (BJT, MOSFET, or LDO regulator)    and must be confirmed from the specific datasheet.

Applications

  • LDO linear regulators (e.g., LM1117, SGM2212)
  • Medium-power MOSFETs and smart power switches
  • DC/DC converters and voltage regulators
  • Consumer electronics, industrial control, and automotive modules

Thermal Design Note

To achieve rated power dissipation, the central tab must be soldered to a    generous copper pour on the PCB top layer, with multiple thermal vias    connecting to an internal ground plane. Reflow soldering is standard, but the    large thermal mass of the tab requires careful profile setup.