LMS1585A/LMS1587
5A and 3A Low Dropout Fast Response Regulators
General Description
The LMS1585A and LMS1587 are low dropout positive regu-
lators with output load current of 5A and 3A respectively.
Their low dropout voltage (1.2V) and fast transient response
make them an excellent solution for low voltage micropro-
cessor applications.
The LMS1585A/87 are available in adjustable versions,
which can set the output voltage with only two external
resistors. In addition, they are also available in 1.5V and
3.3V fixed voltage versions (Note 9).
The LMS1585A/87 circuits include a zener trimmed bandgap
reference, current limiting and thermal shutdown.
The LMS1585A/87 series are available in TO-220 and TO-
263 packages.
Features
n
Fast transient response
n
Available in Adjustable, 1.5V, and 3.3V versions
n
Current limiting and thermal protection
n
Commercial temp. range
0C to 125C
n
Industrial temp. range
-40C to 125C
n
Line regulation
0.005% (typical)
n
Load regulation
0.05% (typical)
n
Direct replacement for LT
TM
1585A/87
Applications
n
Pentium
TM
processor supplies
n
PowerPC
TM
supplies
n
Other microprocessor supplies
n
Low voltage logic supplies
Typical Application
10119701
Connection Diagrams
TO-220
TO-263
10119736
Top View
10119735
Top View
LT is a registered trademark of Linear Technology Corporation
Pentium is a registered trademark of Intel Corporation
PowerPC is a registred trademark of IBM
June 2005
LMS1585A/LMS1587
5A
Low
Dropout
Fast
Response
Regulators
2005 National Semiconductor Corporation
DS101197
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 to Output Voltage
(V
IN
to GND)
13V
Power Dissipation (Note 2)
Internally Limited
Junction Temperature (T
J
) (Note 2)
150C
Storage Temperature Range
-65C to 150C
Lead Temperature
260C, 10 sec
ESD Tolerance (Note 3)
2000V
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 for commercial grade and -40C to 125C for industrial grade.
Symbol
Parameter
Conditions
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Units
V
REF
Reference Voltage
LMS1585A-ADJ
V
IN
-V
OUT
= 3V, I
OUT
= 10mA
10mA
I
OUT
5A, 1.5V V
IN
-V
OUT
5.75V
1.238
1.225
1.25
1.250
1.262
1.275
V
V
LMS1587-ADJ
10mA
I
OUT
3A, 1.5V V
IN
-V
OUT
5.75V
1.225
1.250
1.275
V
V
OUT
Output Voltage
LMS1585A-1.5
I
OUT
= 0mA, V
IN
= 5V
0
I
OUT
5A, 3V V
IN
7V
1.485
1.470
1.500
1.515
1.530
V
V
LMS1585A-3.3
I
OUT
= 0mA, V
IN
= 5V
0
I
OUT
5A, 4.75V V
IN
7V
3.267
3.235
3.300
3.300
3.333
3.365
V
V
LMS1587-1.5
V
IN
= 5V, I
OUT
= 0mA, T
J
= 25C
0
I
OUT
3A, 3V V
IN
7V
1.485
1.470
1.500
1.500
1.515
1.530
V
V
LMS1587-3.3
0
I
OUT
3A, 4.75V V
IN
7V
3.235
3.300
3.365
V
V
OUT
Line Regulation
(Note 6)
LMS1585A/87-ADJ
I
OUT
= 10mA, 2.75V
V
IN
7V
0.005
0.2
%
LMS1585A/87-3.3
I
OUT
= 0mA, 4.75V
V
IN
7V
0.005
0.2
%
LMS1585A/87-1.5
I
OUT
= 0mA, 3V
V
IN
7V
0.005
0.2
%
V
OUT
Load Regulation
(Note 6)
LMS1585A-ADJ
V
IN
-V
OUT
= 3V, 10mA
I
OUT
5A
0.05
0.3
0.5
%
LMS1585A-1.5/LMS1585A-3.3
V
IN
= 5V, 0
I
OUT
5A
0.05
0.05
0.3
0.5
%
LMS1587-ADJ
V
IN
-V
OUT
= 3V, 10mA
I
OUT
3A
0.05
0.05
0.3
0.5
%
LMS1587-1.5/LMS1587-3.3
V
IN
= 5V, 0
I
OUT
3A
0.05
0.05
0.3
0.5
%
%
V
IN
-V
OUT
Dropout Voltage
LMS1585A-ADJ/LMS1587-ADJ
V
REF
= 1%, I
OUT
= 3A
1.15
1.3
V
LMS1585A-3.3/LMS1587-3.3/
LMS1585A-1.5/LMS1587-1.5
V
OUT
= 1%, I
OUT
= 3A
1.15
1.3
V
LMS1585A-ADJ
V
REF
= 1%, I
OUT
= 5A
1.2
1.4
V
LMS1585A-1.5/LMS1585A-3.3
V
OUT
= 1%, I
OUT
= 5A
1.2
1.4
V
LMS1585A/LMS1587
www.national.com
4
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 for commercial grade and -40C to 125C for industrial grade.
Symbol
Parameter
Conditions
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Units
I
LIMIT
Current Limit
LMS1585A-ADJ/LMS1585A-3.3/LMS1585A-1.5
V
IN
-V
OUT
= 5.5V
5.0
6.6
A
LMS1587-ADJ/LMS1587-3.3/LMS1587-1.5
V
IN
-V
OUT
= 5.5V
3.1
4.3
A
Minimum Load
Current (Note 7)
LMS1585A/87-ADJ
1.5V
V
IN
-V
OUT
5.75V
2.0
10.0
mA
Quiescent Current
LMS1585A-3.3/LMS1587-3.3/
LMS1585A-1.5/LMS1587-1.5
V
IN
= 5V
7.0
13.0
mA
Thermal Regulation
T
A
= 25C, 30ms Pulse
0.003
%/W
Ripple Rejection
LMS1585A-ADJ
f
RIPPLE
= 120Hz, V
IN
-V
OUT
= 3V,
I
OUT
= 5A, C
OUT
= 25F Tantalum
72
dB
LMS1585A-1.5
f
RIPPLE
= 120Hz, C
OUT
= 25F Tantalum,
I
OUT
= 5A, V
IN
= 4.5V
60
72
dB
LMS1585A-3.3
f
RIPPLE
= 120Hz, C
OUT
= 25F Tantalum,
I
OUT
= 5A, V
IN
= 6.3V
72
dB
LMS1587-ADJ
f
RIPPLE
= 120Hz, V
IN
-V
OUT
= 3V, I
OUT
= 3A
C
OUT
= 25F Tantalum
72
dB
LMS1587-1.5
f
RIPPLE
= 120Hz, C
OUT
= 25F Tantalum,
I
OUT
= 3A, V
IN
= 4.5V
60
72
dB
LMS1587-3.3
f
RIPPLE
= 120Hz, C
OUT
= 25F Tantalum,
I
OUT
= 3A, V
IN
= 6.3V
72
dB
Adjust Pin Current
55
120
A
Adjust Pin Current
10mA
I
OUT
I
FULLLOAD
,
1.5V
V
IN
-V
OUT
5.75V (Note 8)
0.2
A
Temperature Stability
0.5
%
Long Term Stability
T
A
= 125C, 1000Hrs
0.03
%
RMS Output Noise
(% of V
OUT
)
10Hz
f 10kHz
0.003
%
Thermal Resistance
Junction-to-Case
3-Lead TO-263: Control/Output Section
3-Lead TO-220: Control/Output Section
0.65/2.7
0.65/2.7
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 temperature, and are guaranteed up to the maximum power dissipation of 30W. Power
dissipation is determined by the input/output differential and the output current. Guaranteed maximum power dissipation will not be available over the full input/output
range.
Note 7: The minimum output current required to maintain regulation.
Note 8: I
FULLLOAD
is 5A for LMS1585A and 3A for LMS1587.
Note 9: Consult factory for other fixed voltage options.
LMS1585A/LMS1587
www.national.com
5
PDF 
ZIP
