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
nFast transient response
nAvailable in Adjustable, 1.5V, and 3.3V versions
nCurrent limiting and thermal protection
nCommercial temp. range 0˚C to 125˚C
nIndustrial temp. range −40˚C to 125˚C
nLine regulation 0.005% (typical)
nLoad regulation 0.05% (typical)
nDirect replacement for LT™1585A/87
Applications
nPentium™processor supplies
nPowerPC™supplies
nOther microprocessor supplies
nLow 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
Ordering Information
Output
Current
Package Temperature Range Part Number Transport Media NSC
Drawing
3A TO-263 0˚C to 125˚C LMS1587CS-ADJ Rails
TS3B
LMS1587CSX-ADJ Tape and Reel
LMS1587CS-1.5 Rails
LMS1587CSX-1.5 Tape and Reel
LMS1587CS-3.3 Rails
LMS1587CSX-3.3 Tape and Reel
−40˚C to 125˚C LMS1587IS-ADJ Rails
LMS1587ISX-ADJ Tape and Reel
LMS1587IS-1.5 Rails
LMS1587ISX-1.5 Tape and Reel
LMS1587IS-3.3 Rails
LMS1587ISX-3.3 Tape and Reel
TO-220 0˚C to 125˚C LMS1587CT-ADJ Rails
T03B
LMS1587CT-1.5 Rails
LMS1587CT-3.3 Rails
−40˚C to 125˚C LMS1587IT-ADJ Rails
LMS1587IT-1.5 Rails
LMS1587IT-3.3 Rails
5A TO-263 0˚C to 125˚C LMS1585ACS-ADJ Rails
TS3B
LMS1585ACSX-ADJ Tape and Reel
LMS1585ACS-1.5 Rails
LMS1585ACSX-1.5 Tape and Reel
LMS1585ACS-3.3 Rails
LMS1585ACSX-3.3 Tape and Reel
−40˚C to 125˚C LMS1585AIS-ADJ Rails
LMS1585AISX-ADJ Tape and Reel
LMS1585AIS-1.5 Rails
LMS1585AISX-1.5 Tape and Reel
LMS1585AIS-3.3 Rails
LMS1585AISX-3.3 Tape and Reel
TO-220 0˚C to 125˚C LMS1585ACT-ADJ Rails
T03B
LMS1585ACT-1.5 Rails
LMS1585ACT-3.3 Rails
−40˚C to 125˚C LMS1585AIT-ADJ Rails
LMS1585AIT-1.5 Rails
LMS1585AIT-3.3 Rails
LMS1585A/LMS1587
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Simplified Schematic
10119714
LMS1585A/LMS1587
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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) 150˚C
Storage Temperature Range -65˚C to 150˚C
Lead Temperature 260˚C, 10 sec
ESD Tolerance (Note 3) 2000V
Electrical Characteristics
Typicals and limits appearing in normal type apply for T
J
= 25˚C. Limits appearing in Boldface type apply over the entire junc-
tion temperature range for operation, 0˚C to 125˚C for commercial grade and −40˚C to 125˚C 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
= 25˚C
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
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Electrical Characteristics (Continued)
Typicals and limits appearing in normal type apply for T
J
= 25˚C. Limits appearing in Boldface type apply over the entire junc-
tion temperature range for operation, 0˚C to 125˚C for commercial grade and −40˚C to 125˚C 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
= 25˚C, 30ms Pulse 0.003 %/W
Ripple Rejection LMS1585A-ADJ
f
RIPPLE
= 120Hz, V
IN
−V
OUT
= 3V,
I
OUT
= 5A, C
OUT
= 25µF Tantalum 72 dB
LMS1585A-1.5
f
RIPPLE
= 120Hz, C
OUT
= 25µF Tantalum,
I
OUT
= 5A, V
IN
= 4.5V 60 72 dB
LMS1585A-3.3
f
RIPPLE
= 120Hz, C
OUT
= 25µF 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
= 25µF Tantalum 72 dB
LMS1587-1.5
f
RIPPLE
= 120Hz, C
OUT
= 25µF Tantalum,
I
OUT
= 3A, V
IN
= 4.5V 60 72 dB
LMS1587-3.3
f
RIPPLE
= 120Hz, C
OUT
= 25µF Tantalum,
I
OUT
= 3A, V
IN
= 6.3V 72 dB
Adjust Pin Current 55 120 µA
Adjust Pin Current 10mA ≤I
OUT
≤I
FULLLOAD
,
1.5V ≤V
IN
−V
OUT
≤5.75V (Note 8) 0.2 µA
Temperature Stability 0.5 %
Long Term Stability T
A
= 125˚C, 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 TJ(max) ,θJA, and TA. The maximum allowable power dissipation at any ambient temperature
is PD=(T
J(max)–T A)/θJA. All numbers apply for packages soldered directly into a PC board.
Note 3: For testing purposes, ESD was applied using human body model, 1.5kΩin 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: IFULLLOAD is 5A for LMS1585A and 3A for LMS1587.
Note 9: Consult factory for other fixed voltage options.
LMS1585A/LMS1587
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Application Note
OUTPUT VOLTAGE
The adjustable version develops at 1.25V reference voltage,
(V
REF
), between the output and the adjust terminal. As
shown in Figure 1, this voltage is applied across resistor R1
to generate a constant current I1. This constant current then
flows through R2. The resulting voltage drop across R2 adds
to the reference voltage to sets the desired output voltage.
The current I
ADJ
from the adjustment terminal introduces an
output error. But since it is small (120µA max), it becomes
negligible when R1 is in the 100Ωrange.
For fixed voltage devices, R1 and R2 are integrated inside
the devices.
10119772
FIGURE 1. Basic Adjustable Regulator
LMS1585A/LMS1587
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Physical Dimensions inches (millimeters)
unless otherwise noted
3-Pin TO-263
NS Package Number TS3B
3-Pin TO-220
NS Package Number T03B
LMS1585A/LMS1587
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Notes
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.
For the most current product information visit us at www.national.com.
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LMS1585A/LMS1587 5A Low Dropout Fast Response Regulators
