ETC LM7800

LM140A/LM140/LM340A/LM340/LM7800C
Series 3-Terminal Positive Regulators
General Description
Features
The LM140A/LM140/LM340A/LM340/LM7800C monolithic 3-terminal positive voltage regulators employ internal current-limiting, thermal shutdown and safe-area compensation, making them essentially indestructible. If adequate
heat sinking is provided, they can deliver over 1.0A output
current. 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
voltage regulators, these devices can be used with external
components to obtain adjustable output voltages and currents.
Considerable effort was expended to make the entire series
of regulators easy to use and minimize the number of external components. It is not necessary to bypass the 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.
The 5V, 12V, and 15V regulator options are available in the
steel TO-3 power package. The LM340A/LM340/LM7800C
series is available in the TO-220 plastic power package, and
the LM7805 and LM7812 are also available in the surfacemount TO-263 package.
Y
Y
Y
Y
Y
Y
Y
Y
Complete specifications at 1A load
Output voltage tolerances of g 2% at Tj e 25§ C and
g 4% over the temperature range (LM140A/LM340A)
Line regulation of 0.01% of VOUT/V of DVIN at 1A load
(LM140A/LM340A)
Load regulation of 0.3% of VOUT/A (LM140A/LM340A)
Internal thermal overload protection
Internal short-circuit current limit
Output transistor safe area protection
P a Product Enhancement tested
Device
Output Voltages
Packages
LM140A/LM140 5, 12, 15
TO-3 (K)
LM340A/LM340 5, 12, 15
TO-3 (K), TO-220 (T)
LM7800C
TO-220 (T), TO-263 (S)
(5V and 12V only)
5, 6, 8, 12, 15,
18, 24
Typical Applications
Fixed Output Regulator
Adjustable Output Regulator
Current Regulator
TL/H/7781–1
TL/H/7781 – 3
*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 mF, ceramic disc).
C1995 National Semiconductor Corporation
TL/H/7781
IOUT e
TL/H/7781 – 2
V2-3
a IQ
R1
DIQ e 1.3 mA over line and load changes.
VOUT e 5V a (5V/R1 a IQ) R2 5V/R1 l 3 IQ,
load regulation (Lr) & [(R1 a R2)/R1] (Lr of
LM340-5).
RRD-B30M115/Printed in U. S. A.
LM140A/LM140/LM340A/LM340/LM7800C Series 3-Terminal Positive Regulators
January 1995
Absolute Maximum Ratings
Operating Conditions (Note 1)
(Note 1)
Temperature Range (TA) (Note 2)
LM140A, LM140
LM340A, LM340, LM7805C,
LM7812C, LM7815C
LM7806C, LM7808C, LM7818C,
LM7824C
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
(Note 5)
DC Input Voltage
All Devices except LM7824/LM7824C
35V
LM7824/LM7824C
40V
Internal Power Dissipation (Note 2)
Internally Limited
Maximum Junction Temperature
150§ C
b 55§ C to a 125§ C
0§ C to a 70§ C
0§ C to a 125§ C
b 65§ C to a 150§ C
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
TO-3 Package (K)
300§ C
TO-220 Package (T), TO-263 Package (S)
230§ C
ESD Susceptibility (Note 3)
2 kV
LM140A/LM340A
Electrical Characteristics
IOUT e 1A, b55§ C s TJ s a 150§ C (LM140A), or 0§ C s TJ s a 125§ C (LM340A) unless otherwise specified (Note 4)
Symbol
Output Voltage
5V
12V
Input Voltage (unless otherwise noted)
10V
19V
Parameter
VO
Output Voltage
Conditions
Min Typ Max Min
TJ e 25§ C
4.9
DVO
Line Regulation
DVO
Load Regulation
Quiescent Current
Quiescent Current
Change
15
IO e 500 mA
DVIN
mV
V
TJ e 25§ C
DVIN
3
10
4
18
4
22
(7.5 s VIN s 20) (14.5 s VIN s 27) (17.5 s VIN s 30)
mV
V
4
12
(8 s VIN s 12)
9
30
(16 s VIN s 22)
10
30
(20 s VIN s 26)
mV
mV
V
10
12
12
35
21
mV
mV
TJ e 25§ C 5 mA s IO s 1.5A
250 mA s IO s 750 mA
75
mV
6
6.5
6
6.5
6
6.5
mA
mA
0.5
0.5
0.5
mA
0.8
0.8
0.8
(7.5 s VIN s 20) (14.8 s VIN s 27) (17.9 s VIN s 30)
mA
V
0.8
(8 s VIN s 25)
Output Noise Voltage TA e 25§ C, 10 Hz s f s 100 kHz
DVIN Ripple Rejection
DVOUT
TJ e 25§ C, f e 120 Hz, IO e 1A
or f e 120 Hz, IO e 500 mA,
Over Temperature,
VMIN s VIN s VMAX
RO
Dropout Voltage
Output Resistance
Short-Circuit Current
Peak Output Current
Average TC of VO
TJ e 25§ C, IO e 1A
f e 1 kHz
TJ e 25§ C
TJ e 25§ C
Min, TJ e 0§ C, IO e 5 mA
VIN
Input Voltage
TJ e 25§ C
Required to Maintain
Line Regulation
0.8
(15 s VIN s 30)
40
68
68
80
(8 s VIN s 18)
7.5
0.8
(17.9 s VIN s 30)
mA
V
90
mV
70
dB
dB
75
61
61
72
60
60
(15 s VIN s 25) (18.5 s VIN s 28.5)
2.0
8
2.1
2.4
b 0.6
2
32
19
60
5 mA s IO s 1A
TJ e 25§ C, IO e 1A
VMIN s VIN s VMAX
25
15
25
TJ e 25§ C
IO e 500 mA
VMIN s VIN s VMAX
VN
Max
V
Over Temperature
DIQ
12.25 14.7
Units
Typ
V
V
Over Temperature,
5 mA s IO s 1A
IQ
12
Min
15.3
TJ e 25§ C
Over Temperature
DVIN
5.1 11.75
23V
Typ Max
4.8
5.2 11.5
12.5 14.4
15.6
(7.5 s VIN s 20) (14.8 s VIN s 27) (17.9 s VIN s 30)
10
18
22
(7.5 s VIN s 20) (14.8 s VIN s 27) (17.9 s VIN s 30)
PD s 15W, 5 mA s IO s 1A
VMIN s VIN s VMAX
5
15V
2.0
18
1.5
2.4
b 1.5
14.5
2.0
19
1.2
2.4
b 1.8
17.5
V
V
mX
A
A
mV/§ C
V
LM140
Electrical Characteristics (Note 4) b55§ C s TJ s a 150§ C unless otherwise specified
Symbol
Output Voltage
5V
12V
Input Voltage (unless otherwise noted)
10V
19V
Parameter
VO
DVO
Output Voltage
Line Regulation
Conditions
Min
Load Regulation
12
12.5
TJ e 25§ C
Units
Min
Typ
Max
14.4
15
15.6
V
14.25
15.75
(18.5 s VIN s 30)
V
V
3
50
(7 s VIN s 25)
4
120
(14.5 s VIN s 30)
4
150
(17.5 s VIN s 30)
mV
V
50
(8 s VIN s 20)
120
(15 s VIN s 27)
150
(18.5 s VIN s 30)
mV
V
50
(7.5 s VIN s 20)
120
(14.6 s VIN s 27)
150
(17.7 s VIN s 30)
mV
V
b 55§ C s TJ s a 150§ C
DVIN
25
(8 s VIN s 12)
60
(16 s VIN s 22)
75
(20 s VIN s 26)
mV
V
5 mA s IO s 1.5A
250 mA s IP s 750 mA
10
12
12
150
75
mV
mV
TJ e 25§ C
DVIN
IQ
Quiescent Current
IO s 1A
DIQ
Quiescent Current
Change
5 mA s IO s 1A
TJ e 25§ C
b 55§ C s TJ s a 150§ C
50
25
120
60
50
120
150
mV
6
7
6
7
6
7
mA
mA
0.5
0.5
0.5
mA
TJ e 25§ C, IO s 1A
VMIN s VIN s VMAX
0.8
(8 s VIN s 20)
0.8
(15 s VIN s 27)
0.8
(18.5 s VIN s 30)
mA
V
IO e 500 mA, b 55§ C s TJ s a 150§ C
VMIN s VIN s VMAX
0.8
(8 s VIN s 25)
0.8
(15 s VIN s 30)
0.8
(18.5 s VIN s 30)
mA
V
Output Noise Voltage TA e 25§ C, 10 Hz s f s 100 kHz
DVIN Ripple Rejection
DVOUT
11.5
4.8
b 55§ C s TJ s a 150§ C,
5 mA s IO s 1A
VN
Max
4.75
5.25 11.4
12.6
(8 s VIN s 20)
(15.5 s VIN s 27)
IO s 1A
5.2
Typ
PD s 15W, 5 mA s IO s 1A
VMIN s VIN s VMAX
IO e 500 mA TJ e 25§ C
DVIN
5
23V
Min
TJ e 25§ C, 5 mA s IO s 1A
b 55§ C s TJ s a 150§ C
DVIN
DVO
Typ Max
15V
f e 120 Hz
Ð
40
IO s 1A, TJ e 25§ C or
IO s 500 mA,
b 55§ C s TJ s a 150§ C
VMIN s VIN s VMAX
RO
Dropout Voltage
Output Resistance
Short-Circuit Current
Peak Output Current
Average TC of VOUT
VIN
Input Voltage
TJ e 25§ C, IO s 1A
Required to Maintain
Line Regulation
68
68
75
61
61
72
60
60
90
mV
70
dB
dB
(8 s VIN s 18)
(15 s VIN s 25)
(18.5 s VIN s 28.5)
V
2.0
8
2.1
2.4
b 0.6
2.0
18
1.5
2.4
b 1.5
2.0
19
1.2
2.4
b 1.8
V
mX
A
A
mV/§ C
TJ e 25§ C, IO e 1A
f e 1 kHz
TJ e 25§ C
TJ e 25§ C
0§ C s TJ s a 150§ C, IO e 5 mA
7.5
3
80
14.6
17.7
V
LM340/LM7800C
Electrical Characteristics (Note 4) 0§ C s TJ s a 125§ C unless otherwise specified
Symbol
Output Voltage
5V
12V
Input Voltage (unless otherwise noted)
10V
19V
Parameter
VO
DVO
Output Voltage
Line Regulation
Conditions
15V
23V
Units
Min
Typ
Max
Min
Typ
Max
TJ e 25§ C, 5 mA s IO s 1A
4.8
5
5.2
11.5
12
12.5
PD s 15W, 5 mA s IO s 1A
VMIN s VIN s VMAX
4.75
5.25
(7.5 s VIN s 20)
11.4
12.6
(14.5 s VIN s 27)
3
50
(7 s VIN s 25)
4
120
(14.5 s VIN s 30)
4
150
(17.5 s VIN s 30)
mV
V
50
(8 s VIN s 20)
120
(15 s VIN s 27)
150
(18.5 s VIN s 30)
mV
V
50
(7.5 s VIN s 20)
120
(14.6 s VIN s 27)
150
(17.7 s VIN s 30)
mV
V
25
(8 s VIN s 12)
60
(16 s VIN s 22)
75
(20 s VIN s 26)
mV
V
10
12
12
mV
mV
IO e 500 mA TJ e 25§ C
DVIN
0§ C s TJ s a 125§ C
DVIN
IO s 1A
TJ e 25§ C
DVIN
0§ C s TJ s a 125§ C
DVIN
TJ e 25§ C
5 mA s IO s 1.5A
250 mA s IO s 750 mA
Typ
Max
14.4
15
15.6
V
14.25
15.75
(17.5 s VIN s 30)
V
V
DVO
Load Regulation
5 mA s IO s 1A, 0§ C s TJ s a 125§ C
50
120
150
mV
IQ
Quiescent Current
IO s 1A
8
8.5
8
8.5
8
8.5
mA
mA
DIQ
Quiescent Current
Change
5 mA s IO s 1A
0.5
0.5
0.5
mA
1.0
(7.5 s VIN s 20)
1.0
(14.8 s VIN s 27)
1.0
(17.9 s VIN s 30)
mA
V
1.0
(7 s VIN s 25)
1.0
(14.5 s VIN s 30)
1.0
(17.5 s VIN s 30)
mA
V
TJ e 25§ C
0§ C s TJ s a 125§ C
TJ e 25§ C, IO s 1A
VMIN s VIN s VMAX
IO s 500 mA, 0§ C s TJ s a 125§ C
VMIN s VIN s VMAX
VN
Output Noise Voltage TA e 25§ C, 10 Hz s f s 100 kHz
DVIN Ripple Rejection
DVOUT
IO s 1A, TJ e 25§ C
or IO s 500 mA,
f e 120 Hz
0§ C s TJ s a 125§ C
VMIN s VIN s VMAX
RO
Dropout Voltage
Output Resistance
Short-Circuit Current
Peak Output Current
Average TC of VOUT
TJ e 25§ C, IO e 1A
f e 1 kHz
TJ e 25§ C
TJ e 25§ C
0§ C s TJ s a 125§ C, IO e 5 mA
VIN
Input Voltage
TJ e 25§ C, IO s 1A
Required to Maintain
Line Regulation
Ð
50
25
Min
40
62
62
80
120
60
75
55
55
72
54
54
150
75
90
mV
70
dB
dB
(8 s VIN s 18)
(15 s VIN s 25)
(18.5 s VIN s 28.5)
V
2.0
8
2.1
2.4
b 0.6
2.0
18
1.5
2.4
b 1.5
2.0
19
1.2
2.4
b 1.8
V
mX
A
A
mV/§ C
7.5
14.6
17.7
V
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Conditions are conditions under which the device
functions but the specifications might not be guaranteed. For guaranteed specifications and test conditions see the Electrical Characteristics.
Note 2: The maximum allowable power dissipation at any ambient temperature is a function of the maximum junction temperature for operation (TJMAX e 125§ C or
150§ C), the junction-to-ambient thermal resistance (iJA), and the ambient temperature (TA). PDMAX e (TJMAX b TA)/iJA. If this dissipation is exceeded, the die
temperature will rise above TJMAX and the electrical specifications do not apply. If the die temperature rises above 150§ C, the device will go into thermal shutdown.
For the TO-3 package (K, KC), the junction-to-ambient thermal resistance (iJA) is 39§ C/W. When using a heatsink, iJA is the sum of the 4§ C/W junction-to-case
thermal resistance (iJC) of the TO-3 package and the case-to-ambient thermal resistance of the heatsink. For the TO-220 package (T), iJA is 54§ C/W and iJC is
4§ C/W.
If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package: Using 0.5
square inches of copper area, iJA is 50§ C/W; with 1 square inch of copper area, iJA is 37§ G/W; and with 1.6 or more inches of copper area, iJA is 32§ C/W.
Note 3: ESD rating is based on the human body model, 100 pF discharged through 1.5 kX.
Note 4: All characteristics are measured with a 0.22 mF capacitor from input to ground and a 0.1 mF capacitor from output to ground. All characteristics except
noise voltage and ripple rejection ratio are measured using pulse techniques (tw s 10 ms, duty cycle s 5%). Output voltage changes due to changes in internal
temperature must be taken into account separately.
Note 5: A military RETS specification is available on request. At the time of printing, the military RETS specifications for the LM140AK-5.0/883, LM140AK-12/883,
and LM140AK-15/883 complied with the min and max limits for the respective versions of the LM140A. At the time of printing, the military RETS specifications for
the LM140K-5.0/883, LM140K-12/883, and LM140K-15/883 complied with the min and max limits for the respective versions of the LM140. The LM140H/883,
LM140K/883, and LM140AK/883 may also be procured as a Standard Military Drawing.
4
LM7806C
Electrical Characteristics
0§ C s TJ s a 150§ C, VI e 11V, IO e 500 mA, CI e 0.33 mF, CO e 0.1 mF, unless otherwise specified
Symbol
Parameter
Conditions (Note 4)
VO
Output Voltage
TJ e 25§ C
DVO
Line Regulation
TJ e 25§ C
DVO
Load Regulation
TJ e 25§ C
Min
Typ
Max
Units
5.75
6.0
6.25
V
8.0V s VI s 25V
5.0
120
9.0V s VI s 13V
1.5
60
5.0 mA s IO s 1.5A
14
120
250 mA s IO s 750 mA
4.0
60
VO
Output Voltage
8.0V s VI s 21V, 5.0 mA s IO s 1.0A, P s 15W
IQ
Quiescent Current
TJ e 25§ C
DIQ
Quiescent Current
Change
VN
5.7
4.3
V
8.0
mA
With Line
8.0V s VI s 25V
1.3
5.0 mA s IO s 1.0A
0.5
TA e 25§ C, 10 Hz s f s 100 kHz
DVI/DVO
Ripple Rejection
f e 120 Hz, IO e 350 mA, TJ e 25§ C
VDO
Dropout Voltage
IO e 1.0A, TJ e 25§ C
RO
Output Resistance
f e 1.0 kHz
IOS
Output Short Circuit Current
IPK
DVO/DT
59
mV
6.3
With Load
Noise
mV
mA
45
mV
75
dB
2.0
V
9
mX
TJ e 25§ C, VI e 35V
550
mA
Peak Output Current
TJ e 25§ C
2.2
A
Average Temperature
Coefficient of Output Voltage
IO e 5.0 mA, 0§ C s TA s a 125§ C
0.8
mV/§ C
LM7808C
Electrical Characteristics
0§ C s TJ s a 150§ C, VI e 14V, IO e 500 mA, CI e 0.33 mF, CO e 0.1 mF, unless otherwise specified
Symbol
Parameter
LM7808C
Conditions (Note 4)
Min
VO
Output Voltage
TJ e 25§ C
DVO
Line Regulation
TJ e 25§ C
DVO
Load Regulation
7.7
TJ e 25§ C
Typ
Units
Max
8.0
8.3
10.5V s VI s 25V
6.0
160
11.0V s VI s 17V
2.0
80
5.0 mA s IO s 1.5A
12
160
250 mA s IO s 750 mA
4.0
80
VO
Output Voltage
11.5V s VI s 23V, 5.0 mA s IO s 1.0A, P s 15W
IQ
Quiescent Current
TJ e 25§ C
DIQ
Quiescent
Current Change
7.6
4.3
V
mV
mV
8.4
V
8.0
mA
With Line
11.5V s VI s 25V
1.0
With Load
5.0 mA s IO s 1.0A
0.5
mA
VN
Noise
TA e 25§ C, 10 Hz s f s 100 kHz
DVI/DVO
Ripple Rejection
f e 120 Hz, IO e 350 mA, TJ e 25§ C
VDO
Dropout Voltage
IO e 1.0A, TJ e 25§ C
2.0
V
RO
Output Resistance
f e 1.0 kHz
16
mX
IOS
Output Short Circuit Current
TJ e 25§ C, VI e 35V
0.45
A
IPK
Peak Output Current
TJ e 25§ C
2.2
A
DVO/DT
Average Temperature
Coefficient of Output Voltage
IO e 5.0 mA
0.8
mV/§ C
56
52
mV
72
dB
Note 4: All characteristics are measured with a 0.22 mF capacitor from input to ground and a 0.1 mF capacitor from output to ground. All characteristics except
noise voltage and ripple rejection ratio are measured using pulse techniques (tw s 10 ms, duty cycle s 5%). Output voltage changes due to changes in internal
temperature must be taken into account separately.
5
LM7818C
Electrical Characteristics
0§ C s TJ s a 150§ C, VI e 27V, IO e 500 mA, CI e 0.33 mF, CO e 0.1 mF, unless otherwise specified
Symbol
Parameter
VO
Output Voltage
TJ e 25§ C
DVO
Line Regulation
TJ e 25§ C
DVO
LM7818C
Conditions (Note 4)
Load Regulation
TJ e 25§ C
Units
Min
Typ
Max
17.3
18.0
18.7
21V s VI s 33V
15
360
24V s VI s 30V
5.0
180
5.0 mA s IO s 1.5A
12
360
250 mA s IO s 750 mA
4.0
180
VO
Output Voltage
22V s VI s 33V, 5.0 mA s IO s 1.0A, P s 15W
IQ
Quiescent Current
TJ e 25§ C
DIQ
Quiescent
Current Change
17.1
4.5
V
mV
mV
18.9
V
8.0
mA
With Line
22V s VI s 33V
1.0
With Load
5.0 mA s IO s 1.0A
0.5
mA
VN
Noise
TA e 25§ C, 10 Hz s f s 100 kHz
DVI/DVO
Ripple Rejection
f e 120 Hz, IO e 350 mA, TJ e 25§ C
VDO
Dropout Voltage
IO e 1.0A, TJ e 25§ C
2.0
V
RO
Output Resistance
f e 1.0 kHz
22
mX
IOS
Output Short Circuit Current
TJ e 25§ C, VI e 35V
0.20
A
IPK
Peak Output Current
TJ e 25§ C
2.1
A
DVO/DT
Average Temperature
Coefficient of Output Voltage
IO e 5.0 mA
1.0
mV/§ C
53
110
mV
69
dB
LM7824C
Electrical Characteristics
0§ C s TJ s a 150§ C, VI e 33V, IO e 500 mA, CI e 0.33 mF, CO e 0.1 mF, unless otherwise specified
Symbol
Parameter
VO
Output Voltage
TJ e 25§ C
DVO
Line Regulation
TJ e 25§ C
DVO
LM7824C
Conditions (Note 4)
Load Regulation
TJ e 25§ C
Units
Min
Typ
Max
23.0
24.0
25.0
27V s VI s 38V
18
480
30V s VI s 36V
6.0
240
5.0 mA s IO s 1.5A
12
480
250 mA s IO s 750 mA
4.0
240
VO
Output Voltage
28V s VI s 38V, 5.0 mA s IO s 1.0A, P s 15W
IQ
Quiescent Current
TJ e 25§ C
DIQ
Quiescent
Current Change
22.8
4.6
V
mV
mV
25.2
V
8.0
mA
With Line
28V s VI s 38V
1.0
With Load
5.0 mA s IO s 1.0A
0.5
mA
VN
Noise
TA e 25§ C, 10 Hz s f s 100 kHz
DVI/DVO
Ripple Rejection
f e 120 Hz, IO e 350 mA, TJ e 25§ C
VDO
Dropout Voltage
IO e 1.0A, TJ e 25§ C
2.0
V
RO
Output Resistance
f e 1.0 kHz
28
mX
IOS
Output Short Circuit Current
TJ e 25§ C, VI e 35V
0.15
A
IPK
Peak Output Current
TJ e 25§ C
2.1
A
DVO/DT
Average Temperature
Coefficient of Output Voltage
IO e 5.0 mA
1.5
mV/§ C
50
170
mV
66
dB
Note 4: All characteristics are measured with a 0.22 mF capacitor from input to ground and a 0.1 mF capacitor from output to ground. All characteristics except
noise voltage and ripple rejection ratio are measured using pulse techniques (tw s 10 ms, duty cycle s 5%). Output voltage changes due to changes in internal
temperature must be taken into account separately.
6
Typical Performance Characteristics
Maximum Average Power
Dissipation
Maximum Average Power
Dissipation
Maximum Power
Dissipation (TO-263)
(See Note 2)
Output Voltage (Normalized
to 1V at Tj e 25§ C)
Ripple Rejection
Ripple Rejection
Dropout Characteristics
Quiescent Current
Note: Shaded area refers to LM340A/LM340,
LM7805C, LM7812C and LM7815C.
Output Impedance
Note: Shaded area refers to LM340A/LM340,
LM7805C, LM7812C and LM7815C.
Peak Output Current
Dropout Voltage
Note: Shaded area refers to LM340A/LM340,
LM7805C, LM7812C and LM7815C.
7
Quiescent Current
TL/H/7781 – 4
Typical Performance Characteristics
(Continued)
Load Regulation
140AK-5.0, VIN e 10V, TA e 25§ C
Line Regulation
140AK-5.0, IOUT e 1A, TA e 25§ C
TL/H/7781 – 5
TL/H/7781 – 6
Equivalent Schematic
TL/H/7781 – 7
8
Application Hints
The LM340/LM78XX series is designed with thermal protection, output short-circuit protection and output transistor
safe area protection. However, as with any IC regulator, it
becomes necessary to take precautions to assure that the
regulator is not inadvertently damaged. The following describes possible misapplications and methods to prevent
damage to the regulator.
Shorting the Regulator Input: When using large capacitors at the output of these regulators, a protection diode
connected input to output (Figure 1) may be required if the
input is shorted to ground. Without the protection diode, an
input short will cause the input to rapidly approach ground
potential, while the output remains near the initial VOUT because of the stored charge in the large output capacitor.
The capacitor will then discharge through a large internal
input to output diode and parasitic transistors. If the energy
released by the capacitor is large enough, this diode, low
current metal and the regulator will be destroyed. The fast
diode in Figure 1 will shunt most of the capacitors discharge
current around the regulator. Generally no protection diode
is required for values of output capacitance s 10 mF.
Raising the Output Voltage above the Input Voltage:
Since the output of the device does not sink current, forcing
the output high can cause damage to internal low current
paths in a manner similar to that just described in the
‘‘Shorting the Regulator Input’’ section.
Regulator Floating Ground (Figure 2) : When the ground
pin alone becomes disconnected, the output approaches
the unregulated input, causing possible damage to other circuits connected to VOUT. If ground is reconnected with power ‘‘ON’’, damage may also occur to the regulator. This fault
is most likely to occur when plugging in regulators or modules with on card regulators into powered up sockets. Power
should be turned off first, thermal limit ceases operating, or
ground should be connected first if power must be left on.
Transient Voltages: If transients exceed the maximum rated input voltage of the device, or reach more than 0.8V
below ground and have sufficient energy, they will damage
the regulator. The solution is to use a large input capacitor,
a series input breakdown diode, a choke, a transient suppressor or a combination of these.
TL/H/7781 – 9
FIGURE 2. Regulator Floating Ground
TL/H/7781 – 8
FIGURE 1. Input Short
TL/H/7781 – 10
FIGURE 3. Transients
9
Typical Applications
Fixed Output Regulator
High Input Voltage Circuits
TL/H/7781–13
TL/H/7781 – 14
Note 1: Bypass capacitors are recommended for optimum stability and transient response, and should be located as close as possible to the regulator.
TL/H/7781 – 15
High Current Voltage Regulator
b(Q1) t
R1 e
IO Max
IREG Max
0.9
b(Q1) VBE(Q1)
e
IREG
IREG Max (b a 1) b IO Max
TL/H/7781 – 16
High Output Current, Short Circuit Protected
RSC e
R1 e
0.8
ISC
bVBE(Q1)
IREG Max (b a 1) b IO Max
TL/H/7781 – 17
Positive and Negative Regulator
TL/H/7781 – 18
10
Connection Diagrams and Ordering Information
TO-220 Power Package (T)
TO-3 Metal Can Package (K)
TL/H/7781 – 11
TL/H/7781 – 12
Bottom View
Top View
Steel Package Order Numbers:
LM140K-5.0
LM140K-12
LM140K-15
LM340AK-5.0
LM340K-12
LM340K-15
LM340K-5.0
See Package Number K02A
Plastic Package Order Numbers:
LM340AT-5.0 LM340T-5.0
LM340AT-12 LM340T-12
LM340AT-15 LM340T-15
LM7805CT
LM7812CT
LM7815CT
LM7806CT
LM7808CT
LM7818CT
LM7824CT
See Package Number T03B
LM140AK-5.0/883 LM140AK-12/883 LM140AK-15/883
LM140K-5.0/883 LM140K-12/883 LM140K-15/883
See Package Number K02C
TO-39 Metal Can Package (H)
TO-263 Surface-Mount Package (S)
TL/H/7781 – 20
Top View
TL/H/7781 – 19
TL/H/7781 – 21
Top View
Side View
Metal Can Order Numbers ² :
LM140H-5.0/883
LM140H-6.0/883
LM140H-8.0/883
LM140H-12/883
LM140H-15/883
LM140H-24/883
See Package Number H03A
Surface-Mount Package Order Numbers:
LM7805S
LM7812S
See Package Number TS3B
² The specifications for the LM140H/883 devices are not contained in this datasheet. If specifications for these devices
are required, contact the National Semiconductor Sales Office/Distributors.
11
Physical Dimensions inches (millimeters)
TO-3 Metal Can Package (K)
Order Number LM340AK-5.0, LM140K-5.0, LM340K-5.0, LM140K-12, LM340K-12,
LM140K-15, LM340K-15, LM7806CK, LM7808CK, LM7818CK or LM7824CK
NS Package Number K02A
12
Physical Dimensions inches (millimeters) (Continued)
TO-3 Metal Can Package (K)
Mil-Aero Products
Order Number LM140AK-5.0/883, LM140K-5.0/883, LM140AK-12/883,
LM140K-12/883, LM140AK-15/883 or LM140K-15/883
NS Package Number K02C
TO-263 Surface-Mount Package (S)
Order Number LM7805S or LM7812S
NS Package Number TS3B
13
LM140A/LM140/LM340A/LM340/LM7800C Series 3-Terminal Positive Regulators
Physical Dimensions inches (millimeters) (Continued)
TO-220 Power Package (T)
Order Number LM340AT/LM340T-5.0, LM340AT/LM340T-12, LM340AT/LM340T-15,
LM7805CT, LM7812CT, LM7815CT, LM7806CT, LM7808CT, LM7818CT or LM7824CT
NS Package Number T03B
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