LM78XX
Series Voltage Regulators
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.
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.
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-
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.
For output voltage other than 5V, 12V and 15V the LM117
series provides an output voltage range from 1.2V to 57V.
Features
nOutput current in excess of 1A
nInternal thermal overload protection
nNo external components required
nOutput transistor safe area protection
nInternal short circuit current limit
nAvailable in the aluminum TO-3 package
Voltage Range
LM7805C 5V
LM7812C 12V
LM7815C 15V
Connection Diagrams
Metal Can Package
TO-3 (K)
Aluminum
DS007746-2
Bottom View
Order Number LM7805CK,
LM7812CK or LM7815CK
See NS Package Number KC02A
Plastic Package
TO-220 (T)
DS007746-3
Top View
Order Number LM7805CT,
LM7812CT or LM7815CT
See NS Package Number T03B
May 2000
LM78XX Series Voltage Regulators
© 2000 National Semiconductor Corporation DS007746 www.national.com
Schematic
DS007746-1
LM78XX
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Absolute Maximum Ratings (Note 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Input Voltage
(V
O
= 5V, 12V and 15V) 35V
Internal Power Dissipation (Note 1) Internally Limited
Operating Temperature Range (T
A
) 0˚C to +70˚C
Maximum Junction Temperature
(K Package) 150˚C
(T Package) 150˚C
Storage Temperature Range −65˚C to +150˚C
Lead Temperature (Soldering, 10 sec.)
TO-3 Package K 300˚C
TO-220 Package T 230˚C
Electrical Characteristics LM78XXC (Note 2)
0˚C ≤T
J
≤125˚C unless otherwise noted.
Output Voltage 5V 12V 15V
Input Voltage (unless otherwise noted) 10V 19V 23V Units
Symbol Parameter Conditions Min Typ Max Min Typ Max Min Typ Max
V
O
Output Voltage Tj = 25˚C, 5 mA ≤I
O
≤1A 4.8 5 5.2 11.5 12 12.5 14.4 15 15.6 V
P
D
≤15W, 5 mA ≤I
O
≤1A 4.75 5.25 11.4 12.6 14.25 15.75 V
V
MIN
≤V
IN
≤V
MAX
(7.5 ≤V
IN
≤20) (14.5 ≤V
IN
≤
27) (17.5 ≤V
IN
≤
30) V
∆V
O
Line Regulation I
O
= 500
mA Tj = 25˚C 3 50 4 120 4 150 mV
∆V
IN
(7 ≤V
IN
≤25) 14.5 ≤V
IN
≤30) (17.5 ≤V
IN
≤
30) V
0˚C ≤Tj ≤+125˚C 50 120 150 mV
∆V
IN
(8 ≤V
IN
≤20) (15 ≤V
IN
≤27) (18.5 ≤V
IN
≤
30) V
I
O
≤1A Tj = 25˚C 50 120 150 mV
∆V
IN
(7.5 ≤V
IN
≤20) (14.6 ≤V
IN
≤
27) (17.7 ≤V
IN
≤
30) V
0˚C ≤Tj ≤+125˚C 25 60 75 mV
∆V
IN
(8 ≤V
IN
≤12) (16 ≤V
IN
≤22) (20 ≤V
IN
≤26) V
∆V
O
Load Regulation Tj = 25˚C 5 mA ≤I
O
≤1.5A 10 50 12 120 12 150 mV
250 mA ≤I
O
≤
750 mA 25 60 75 mV
5mA≤I
O
≤1A, 0˚C ≤Tj ≤
+125˚C 50 120 150 mV
I
Q
Quiescent Current I
O
≤1A Tj = 25˚C 8 8 8 mA
0˚C ≤Tj ≤+125˚C 8.5 8.5 8.5 mA
∆I
Q
Quiescent Current 5 mA ≤I
O
≤1A 0.5 0.5 0.5 mA
Change Tj = 25˚C, I
O
≤1A 1.0 1.0 1.0 mA
V
MIN
≤V
IN
≤V
MAX
(7.5 ≤V
IN
≤20) (14.8 ≤V
IN
≤27) (17.9 ≤V
IN
≤
30) V
I
O
≤500 mA, 0˚C ≤Tj ≤+125˚C 1.0 1.0 1.0 mA
V
MIN
≤V
IN
≤V
MAX
(7 ≤V
IN
≤25) (14.5 ≤V
IN
≤30) (17.5 ≤V
IN
≤
30) V
V
N
Output Noise
Voltage T
A
=25˚C, 10 Hz ≤f≤100 kHz 40 75 90 µV
Ripple Rejection I
O
≤1A, Tj = 25˚C
or 62 80 55 72 54 70 dB
f = 120 Hz I
O
≤500 mA 62 55 54 dB
0˚C ≤Tj ≤+125˚C
V
MIN
≤V
IN
≤V
MAX
(8 ≤V
IN
≤18) (15 ≤V
IN
≤25) (18.5 ≤V
IN
≤
28.5) V
R
O
Dropout Voltage Tj = 25˚C, I
OUT
= 1A 2.0 2.0 2.0 V
Output Resistance f = 1 kHz 8 18 19 mΩ
LM78XX
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Electrical Characteristics LM78XXC (Note 2) (Continued)
0˚C ≤T
J
≤125˚C unless otherwise noted.
Output Voltage 5V 12V 15V
Input Voltage (unless otherwise noted) 10V 19V 23V Units
Symbol Parameter Conditions Min Typ Max Min Typ Max Min Typ Max
Short-Circuit
Current Tj = 25˚C 2.1 1.5 1.2 A
Peak Output
Current Tj = 25˚C 2.4 2.4 2.4 A
Average TC of
V
OUT
0˚C ≤Tj ≤+125˚C, I
O
= 5 mA 0.6 1.5 1.8 mV/˚C
V
IN
Input Voltage
Required to
Maintain Tj = 25˚C, I
O
≤1A 7.5 14.6 17.7 V
Line Regulation
Note 1: Thermal resistance of the TO-3 package (K, KC) is typically 4˚C/W junction to case and 35˚C/W case to ambient.Thermal resistance of the TO-220 package
(T) is typically 4˚C/W junction to case and 50˚C/W case to ambient.
Note 2: All characteristics are measured with capacitor across the input of 0.22 µF, and a capacitor across the output of 0.1µF.All characteristics except noise voltage
and ripple rejection ratio are measured using pulse techniques (tw≤10 ms, duty cycle ≤5%). Output voltage changes due to changes in internal temperature must
be taken into account separately.
Note 3: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and the test conditions, see Elec-
trical Characteristics.
LM78XX
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Typical Performance Characteristics
Maximum Average Power Dissipation
DS007746-5
Maximum Average Power Dissipation
DS007746-6
Peak Output Current
DS007746-7
Output Voltage (Normalized to 1V at T
J
= 25˚C)
DS007746-8
Ripple Rejection
DS007746-9
Ripple Rejection
DS007746-10
LM78XX
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Typical Performance Characteristics (Continued)
Output Impedance
DS007746-11
Dropout Voltage
DS007746-12
Dropout Characteristics
DS007746-13
Quiescent Current
DS007746-14
Quiescent Current
DS007746-15
LM78XX
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Physical Dimensions inches (millimeters) unless otherwise noted
Aluminum Metal Can Package (KC)
Order Number LM7805CK, LM7812CK or LM7815CK
NS Package Number KC02A
LM78XX
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
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Tel: 1-800-272-9959
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www.national.com
TO-220 Package (T)
Order Number LM7805CT, LM7812CT or LM7815CT
NS Package Number T03B
LM78XX Series Voltage Regulators
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
