LM109/LM309 5-Volt Regulator
The LM109 and LM309 are 5‑volt linear regulators offered in TO‑5 and TO‑3 packages. They are intended for local regulation on digital logic cards, providing high output current capability and built‑in protection features such as current limiting and thermal shutdown. The devices are designed for easy use with minimal external components.
The handbook includes detailed electrical characteristics, absolute maximum ratings, typical performance curves, application recommendations, and mechanical dimensions. It also covers protection methods like crowbar over‑voltage circuits and provides guidance for high‑stability and current‑regulation applications.
| Maximum output current (TO‑5 package) | >200 mA |
|---|---|
| Maximum output current (TO‑3 package) | >1 A |
| Thermal shutdown temperature | ≈175 °C |
| Junction‑to‑case thermal resistance (TO‑3) | 25 °C/W |
The LM109 in the TO‑5 package can deliver output currents in excess of 200 mA when adequate heat sinking is provided.