May 2000
LM78XX
Series Voltage Regulators
put, although this does improve transient response. Input by-
passing is needed only if the regulator is located far from the
filter capacitor of the power supply.
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, instrumenta-
tion, HiFi, and other solid state electronic equipment. Al-
though designed primarily as fixed voltage regulators these
devices can be used with external components to obtain ad-
justable voltages and currents.
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
The LM78XX series is available in an aluminum TO-3 pack-
age 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 dissi-
pation. If internal power dissipation becomes too high for the
heat sinking provided, the thermal shutdown circuit takes
over preventing the IC from overheating.
Voltage Range
LM7805C
LM7812C
LM7815C
5V
12V
15V
Considerable effort was expanded to make the LM78XX se-
ries of regulators easy to use and minimize the number of
external components. It is not necessary to bypass the out-
Connection Diagrams
Metal Can Package
TO-3 (K)
Plastic Package
TO-220 (T)
Aluminum
DS007746-3
DS007746-2
Top View
Bottom View
Order Number LM7805CT,
LM7812CT or LM7815CT
See NS Package Number T03B
Order Number LM7805CK,
LM7812CK or LM7815CK
See NS Package Number KC02A
© 2000 National Semiconductor Corporation
DS007746
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