LMS8117A
1A Low-Dropout Linear Regulator
General Description
The LMS8117A is a series of low dropout voltage regulators
with a dropout of 1.2V at 1A of load current. It has the same
pin-out as National Semiconductor's industry standard
LM317.
The LMS8117A is available in an adjustable version, which
can set the output voltage from 1.25V to 13.8V with only two
external resistors. In addition, it is also available in two fixed
voltages, 1.8V and 3.3V.
The LMS8117A offers current limiting and thermal shutdown.
Its circuit includes a zener trimmed bandgap reference to
assure output voltage accuracy to within
1%.
The LMS8117A series is available in SOT-223 and TO-252
D-PAK packages. A minimum of 10F tantalum capacitor is
required at the output to improve the transient response and
stability.
Features
n
Available in 1.8V, 3.3V, and Adjustable Versions
n
Space Saving SOT-223 and TO-252 Packages
n
Current Limiting and Thermal Protection
n
Output Current
1A
n
Temperature Range
0C to 125C
n
Line Regulation
0.2% (Max)
n
Load Regulation
0.4% (Max)
Applications
n
Post Regulator for Switching DC/DC Converter
n
High Efficiency Linear Regulators
n
Battery Charger
n
Battery Powered Instrumentation
Typical Application
Fixed Output Regulator
10119628
April 2005
LMS81
17A
1A
Low-Dropout
Linear
Regulator
2005 National Semiconductor Corporation
DS101196
www.national.com
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Maximum Input Voltage (V
IN
to GND)
LMS8117A-ADJ, LMS8117A-1.8,
LMS8117A-3.3
20V
Power Dissipation (Note 2)
Internally Limited
Junction Temperature (T
J
)
(Note 2)
150C
Storage Temperature Range
-65C to 150C
Soldering Information
Infrared (20 sec)
235C
ESD Tolerance (Note 3)
2000V
Operating Ratings
(Note 1)
Input Voltage (V
IN
to GND)
LMS8117A-ADJ, LMS8117A-1.8,
LMS8117A-3.3
15V
Junction Temperature Range
(T
J
)(Note 2)
0C to 125C
Electrical Characteristics
Typicals and limits appearing in normal type apply for T
J
= 25C. Limits appearing in Boldface type apply over the entire junc-
tion temperature range for operation, 0C to 125C.
Symbol
Parameter
Conditions
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Units
V
REF
Reference Voltage
LMS8117A-ADJ
I
OUT
= 10mA, V
IN
-V
OUT
= 2V, T
J
= 25C
10mA
I
OUT
1A, 1.4V V
IN
-V
OUT
10V
1.238
1.225
1.250
1.250
1.262
1.270
V
V
V
OUT
Output Voltage
LMS8117A-1.8
I
OUT
= 10mA, V
IN
= 3.8V, T
J
= 25C
0
I
OUT
1A, 3.2V V
IN
10V
1.782
1.746
1.800
1.800
1.818
1.854
V
V
LMS8117A-3.3
I
OUT
= 10mA, V
IN
= 5V T
J
= 25C
0
I
OUT
1A, 4.75V V
IN
10V
3.267
3.235
3.300
3.300
3.333
3.365
V
V
V
OUT
Line Regulation (Note
6)
LMS8117A-ADJ
I
OUT
= 10mA, 1.5V
V
IN
-V
OUT
13.75V
0.035
0.2
%
LMS8117A-1.8
I
OUT
= 0mA, 3.2V
V
IN
10V
1
6
mV
LMS8117A-3.3
I
OUT
= 0mA, 4.75V
V
IN
15V
1
6
mV
V
OUT
Load Regulation (Note
6)
LMS8117A-ADJ
V
IN
-V
OUT
= 3V, 10mA
I
OUT
1A
0.2
0.4
%
LMS8117A-1.8
V
IN
= 3.2V, 0
I
OUT
1A
1
10
mV
LMS8117A-3.3
V
IN
= 4.75V, 0
I
OUT
1A
1
10
mV
V
IN
-V
OUT
Dropout Voltage
(Note 7)
I
OUT
= 100mA
1.1
1.15
V
I
OUT
= 500mA
1.15
1.2
V
I
OUT
= 1A
1.2
1.25
V
I
LIMIT
Current Limit
V
IN
-V
OUT
= 5V, T
J
= 25C
1.0
1.4
1.9
A
Minimum Load
Current (Note 8)
LMS8117A-ADJ
V
IN
= 15V
1.7
5
mA
Quiescent Current
LMS8117A-1.8
V
IN
15V
5
10
mA
LMS8117A-3.3
V
IN
15V
5
10
mA
Thermal Regulation
T
A
= 25C, 30ms Pulse
0.01
0.1
%/W
Ripple Regulation
f
RIPPLE
= 120Hz, V
IN
-V
OUT
= 3V
V
RIPPLE
= 1V
PP
60
75
dB
Adjust Pin Current
60
120
A
Adjust Pin Current
Change
10mA
I
OUT
1A,
1.4V
V
IN
-V
OUT
10V
0.2
5
A
LMS81
17A
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3
Electrical Characteristics
(Continued)
Typicals and limits appearing in normal type apply for T
J
= 25C. Limits appearing in Boldface type apply over the entire junc-
tion temperature range for operation, 0C to 125C.
Symbol
Parameter
Conditions
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Units
Temperature Stability
0.5
%
Long Term Stability
T
A
= 125C, 1000Hrs
0.3
%
RMS Output Noise
(% of V
OUT
), 10Hz
f 10kHz
0.003
%
Thermal Resistance
Junction-to-Case
3-Lead SOT-223
3-Lead TO-252
15.0
10
C/W
C/W
Thermal Resistance
Junction-to-Ambient
(No heat sink;
No air flow)
3-Lead SOT-223
3-Lead TO-252 (Note 9)
136
92
C/W
C/W
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: The maximum power dissipation is a function of T
J(MAX)
,
JA
, and T
A
. The maximum allowable power dissipation at any ambient temperature is
P
D
= (T
J(MAX)
T
A
)/
JA
. All numbers apply for packages soldered directly into a PC board.
Note 3: For testing purposes, ESD was applied using human body model, 1.5k
in series with 100pF.
Note 4: Typical Values represent the most likely parametric norm.
Note 5: All limits are guaranteed by testing or statistical analysis.
Note 6: Load and line regulation are measured at constant junction room temperature.
Note 7: The dropout voltage is the input/output differential at which the circuit ceases to regulate against further reduction in input voltage. It is measured when the
output voltage has dropped 100mV from the nominal value obtained at V
IN
= V
OUT
+1.5V.
Note 8: The minimum output current required to maintain regulation.
Note 9: Minimum pad size of 0.038in
2
LMS81
17A
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4
Typical Performance Characteristics
Dropout Voltage (V
IN
-V
OUT
)
Short-Circuit Current
10119622
10119623
Load Regulation
LMS8117A-ADJ Ripple Rejection vs. Current
10119624
10119606
LMS8117A-ADJ Ripple Rejection
Temperature Stability
10119607
10119625
LMS81
17A
www.national.com
5
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