LM309 Datasheet | National Semiconductor

Description The LM109 series are plete 5V regulators fabricated on a single silicon chip. They are designed for local regulation on digital logic cards, eliminating the distribution problems association with single-point regulation. The devices are available in two standard transistor packages. In the solid-kovar TO-5 header, it can deliver output currents in excess of 200 m A, if adequate heat sinking is provided. With the TO-3 power package, the available output current is greater than 1A. The regulators are essentially blowout proof. Current limiting is included to limit the peak output current to a safe value. In addition, thermal shutdown is provided to keep the IC from overheating. If internal dissipation bees too great, the regulator will shut down to prevent excessive heating. Considerable effort was expended to make these devices easy to use and to minimize the number of external ponents. It is not necessary to bypass the output, although this does improve transient response somewhat. Input bypassing is needed, however, if the regulator is located very far from the filter capacitor of the power supply. Stability is also achieved by methods that provide very good rejection of load or line transients as are usually seen with TTL logic. Although designed primarily as a fixed-voltage regulator, the output of the LM109 series can be set to voltages above 5V, as shown. It is also possible to use the circuits as the control element in precision regulators, taking advantage of the good current-handling capability and the thermal overload protection. Features n Specified to be patible, worst case, with TTL and DTL n Output current in excess of 1A n Internal thermal overload protection n No external ponents required Schematic Diagram DS007138-1 © 1999 National Semiconductor Corporation DS007138 .national. Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors...