General Description

The LM78XX series of three terminal regulators is available

with several fixed output voltages making them useful in a

wide range of applications. One of these is local on card

regulation, eliminating the distribution problems associated

with single point regulation. The voltages available allow

these regulators to be used in logic systems, instrumentation,

HiFi, and other solid state electronic equipment. Although

designed primarily as fixed voltage regulators these

devices can be used with external components to obtain adjustable

voltages and currents.

The LM78XX series is available in an aluminum TO-3 package

which will allow over 1.0A load current if adequate heat

sinking is provided. Current limiting is included to limit the

peak output current to a safe value. Safe area protection for

the output transistor is provided to limit internal power dissipation.

If internal power dissipation becomes too high for the

heat sinking provided, the thermal shutdown circuit takes

over preventing the IC from overheating.

Considerable effort was expanded to make the LM78XX series

of regulators easy to use and minimize the number of

external components. It is not necessary to bypass the output, output,

although this does improve transient response. Input bypassing

is needed only if the regulator is located far from the

filter capacitor of the power supply.

For output voltage other than 5V, 12V and 15V the LM117

series provides an output voltage range from 1.2V to 57V.

Features

n Output current in excess of 1A

n Internal thermal overload protection

n No external components required

n Output transistor safe area protection

n Internal short circuit current limit

n Available in the aluminum TO-3 package