LM340/LM78XX Series 3-Terminal Positive Regulators
July 2006
LM340/LM78XX Series
3-Terminal Positive Regulators
General Description
The
LM140/LM340A/LM340/LM78XXC
monolithic
3-terminal positive voltage regulators employ internal
current-limiting, thermal shutdown and safe-area compensa-
tion, making them essentially indestructible. If adequate heat
sinking is provided, they can deliver over 1.0A output cur-
rent. They are intended as fixed voltage regulators in a wide
range of applications including local (on-card) regulation for
elimination of noise and distribution problems associated
with single-point regulation. In addition to use as fixed volt-
age regulators, these devices can be used with external
components to obtain adjustable output voltages and cur-
rents.
Considerable effort was expended to make the entire series
of regulators easy to use and minimize the number of exter-
nal components. It is not necessary to bypass the output,
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.
The 5V, 12V, and 15V regulator options are available in the
steel TO-3 power package. The LM340A/LM340/LM78XXC
series is available in the TO-220 plastic power package, and
the LM340-5.0 is available in the SOT-223 package, as well
as the LM340-5.0 and LM340-12 in the surface-mount TO-
263 package.
Features
n
Complete specifications at 1A load
n
Output voltage tolerances of
±
2% at T
j
= 25˚C and
±
4%
over the temperature range (LM340A)
n
Line regulation of 0.01% of V
OUT
/V of
∆V
IN
at 1A load
(LM340A)
n
Load regulation of 0.3% of V
OUT
/A (LM340A)
n
Internal thermal overload protection
n
Internal short-circuit current limit
n
Output transistor safe area protection
n
P
+
Product Enhancement tested
Typical Applications
Fixed Output Regulator
Adjustable Output Regulator
00778101
*Required if the regulator is located far from the power supply filter.
**Although no output capacitor is needed for stability, it does help transient
response. (If needed, use 0.1 µF, ceramic disc).
00778102
V
OUT
= 5V + (5V/R1 + I
Q
) R2 5V/R1
>
3 I
Q
,
load regulation (L
r
)
≈
[(R1 + R2)/R1] (L
r
of LM340-5).
Current Regulator
Comparison between SOT-223 and D-Pak (TO-252)
Packages
00778103
00778138
Scale 1:1
∆I
Q
= 1.3 mA over line and load changes.
© 2006 National Semiconductor Corporation
DS007781
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LM340/LM78XX
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
(Note 5)
DC Input Voltage
Internal Power Dissipation (Note 2)
Maximum Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
TO-3 Package (K)
300˚C
35V
Internally Limited
150˚C
−65˚C to +150˚C
TO-220 Package (T), TO-263
Package (S)
ESD Susceptibility (Note 3)
230˚C
2 kV
Operating Conditions
(Note 1)
Temperature Range (T
A
) (Note 2)
LM140
LM340A, LM340
LM7808C
−55˚C to +125˚C
0˚C to +125˚C
0˚C to +125˚C
LM340A Electrical Characteristics
I
OUT
= 1A, 0˚C
≤
T
J
≤
+ 125˚C (LM340A) unless otherwise specified (Note 4)
Output Voltage
Symbol
V
O
Input Voltage (unless otherwise noted)
Parameter
Output Voltage
T
J
= 25˚C
P
D
≤
15W, 5 mA
≤
I
O
≤
1A
V
MIN
≤
V
IN
≤
V
MAX
∆V
O
Line Regulation
I
O
= 500 mA
∆V
IN
T
J
= 25˚C
∆V
IN
T
J
= 25˚C
Over Temperature
∆V
IN
∆V
O
Load Regulation
T
J
= 25˚C
5 mA
≤
I
O
≤
1.5A
250 mA
≤
I
O
≤
750
mA
Over Temperature,
5 mA
≤
I
O
≤
1A
I
Q
Quiescent
Current
Quiescent
Current
Change
T
J
= 25˚C
Over Temperature
∆I
Q
5 mA
≤
I
O
≤
1A
T
J
= 25˚C, I
O
= 1A
V
MIN
≤
V
IN
≤
V
MAX
I
O
= 500 mA
V
MIN
≤
V
IN
≤
V
MAX
V
N
Output Noise
Voltage
Ripple Rejection
T
A
= 25˚C, 10 Hz
≤
f
≤
100 kHz
T
J
= 25˚C, f = 120 Hz, I
O
= 1A
or f = 120 Hz, I
O
= 500 mA,
Over Temperature,
V
MIN
≤
V
IN
≤
V
MAX
R
O
Dropout Voltage
Output
Resistance
Short-Circuit
Current
T
J
= 25˚C, I
O
= 1A
f = 1 kHz
T
J
= 25˚C
(8
≤
V
IN
≤
18)
2.0
8
2.1
(15
≤
V
IN
≤
25)
2.0
18
1.5
(18.5
≤
V
IN
≤
28.5)
2.0
19
1.2
V
V
mΩ
A
68
68
40
80
61
61
0.5
0.8
(7.5
≤
V
IN
≤
20)
0.8
(8
≤
V
IN
≤
25)
75
72
60
60
6
6.5
0.5
0.8
(14.8
≤
V
IN
≤
27)
0.8
(15
≤
V
IN
≤
30)
90
70
6
6.5
0.5
0.8
(17.9
≤
V
IN
≤
30)
0.8
(17.9
≤
V
IN
≤
30)
6
6.5
mA
mA
mA
mA
V
mA
V
µV
dB
dB
10
3
Conditions
4.9
4.8
5V
10V
Min Typ Max
5
5.1
5.2
10
(7.5
≤
V
IN
≤
20)
10
4
12
(8
≤
V
IN
≤
12)
25
15
25
12
(7.5
≤
V
IN
≤
20)
4
Min
11.75
11.5
12V
19V
Typ Max
12.5
18
(14.8
≤
V
IN
≤
27)
18
9
30
(16
≤
V
IN
≤
22)
32
19
60
12
(14.5
≤
V
IN
≤
27)
4
Min
14.4
12 12.25 14.7
15V
23V
Typ Max
15
15.3
15.6
22
(17.9
≤
V
IN
≤
30)
22
10
30
(20
≤
V
IN
≤
26)
35
21
75
(17.5
≤
V
IN
≤
30)
V
V
V
mV
V
mV
V
mV
mV
V
mV
mV
mV
Units
(7.5
≤
V
IN
≤
20)
(14.8
≤
V
IN
≤
27)
(17.9
≤
V
IN
≤
30)
3
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