1.0A Low Dropout Voltage
Regulator with Enable
POWER MANAGEMENT
Description
The SC1541 is a high performance low dropout positive
voltage regulator designed for use in applications where
power management is critical, such as battery powered
systems.
Additionally, the SC1541 provides excellent regulation
over variations in line, load and temperature.
Outstanding features include low dropout performance
at rated current, fast transient response, internal
current limiting and thermal shutdown protection of the
output device. A very low quiescent current of 10µA in
shutdown mode reduces power dissipation.
The SC1541 is available with three different voltage
options as standard and two package options, SO-8 and
5-lead TO-263.
SC1541
Features
Low dropout performance, 1.3V max
Full current rating over line and temperature
Fast transient response
+2% total output regulation over line, load
and temperature
10µA max. quiescent current in shutdown
Three fixed output voltages
Line regulation 0.2% max.
Load regulation 0.4% max.
SO-8 and TO-263 packages
Applications
Low voltage microcontrollers
Switching power supply post-regulation
Instantly available circuits
Motherboards
Battery operated equipment
Typical Application Circuit
U1
V
IN
ENABLE SIGNAL
IN
EN
SC1541
OUT
V
OUT
GND
C1
10uF
Tantalum
C2
10uF min.
Tantalum
Notes:
(1) Input and output capacitors should be located close to the device.
(2) Connect all pins to PCB (SO-8 package) for optimal thermal characteristics.
(3) Increasing the output capacitor value will improve the overall transient response.
(4) The device is enabled when V
EN
= V
IN
, and shut down when EN is pulled to ground. EN should not be taken higher
than V
IN
. A CMOS signal referenced to V
IN
would be ideal for switching the SC1541 on and off.
Revision: November 25, 2009
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SC1541
POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not implied.
Parameter
Maximum Input Pin Voltage
Power Dissipation
Thermal Resistance Junction to Case
SO-8
TO-263
Thermal Resistance Junction to Ambient
SO-8
(1)
TO-263
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering) 10 Sec
Symbol
V
IN
, V
EN
P
D
θ
J C
Maximum
7
Internally Limited
39
3
65
60
0 to 125
-65 to 150
300
Units
V
W
°C/W
θ
J A
T
J
T
STG
T
LEAD
°C/W
°C
°C
°C
Note:
(1) 1 inch square of 1/16” FR-4, double sided, 1 oz. minimum copper weight.
Electrical Characteristics
Unless otherwise specified: I
O
= 0mA to 1A, V
EN
= V
IN
, 1.8V Option: V
IN
= 3.2V to 7.0V, 2.5 Option: V
IN
= 3.9V to 7.0V,
3.3V Option: V
IN
= 4.7V to 7.0V. Values in
bold
apply over full operating temperature range.
Parameter
Output Voltage
(1)
Symbol
V
OUT
V
IN
= 5V, I
OUT
= 0mA
Min
-1
-2
Typ
V
OUT
Max
+1
+2
Units
%
Line Regulation
(1)
Load Regulation
(1)
Dropout Voltage
(1)(2)
Current Limit
(1)
Quiescent Current
REG
(LINE)
REG
(LOAD)
V
D
I
CL
I
Q
I
OUT
= 10mA
V
IN
= 5V
I
OUT
= 1A
1.1
V
IN
= V
EN
= 5V
0.035
0.2
1.10
0.2
0.4
1.30
%
%
V
A
5
7
10
mA
V
IN
= 5V, V
EN
< 0.25V
6
8
10
µA
Enable Pin Control Voltage
V
EN
Device OFF
Device ON
0.25
0.45
(V
OUT
+ 0.5)
0.1
15
(V
OUT
+ 0.8)
1.0
25
V
Enable Pin Current
I
EN
V
EN
= 0V, V
IN
= 5V (OFF)
V
EN
= V
IN
= 5V (ON)
µA
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SC1541
PRELIMINARY
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless otherwise specified: I
O
= 0mA to 1A, V
EN
= V
IN
, 1.8V Option: V
IN
= 3.2V to 7.0V, 2.5 Option: V
IN
= 3.9V to 7.0V,
3.3V Option: V
IN
= 4.7V to 7.0V. Values in
bold
apply over full operating temperature range.
Parameter
Temperature Coefficient
Temperature Stability
RMS Output Noise
(3)
Ripple Rejection Ratio
(4)
Symbol
T
C
T
S
V
N
R
A
V
IN
= 5V
Min
Typ
0.005
0.5
0.003
Max
Units
%/C
%
%V
OUT
dB
60
72
Notes:
(1) Low duty cycle pulse testing with Kelvin connections required.
(2)
∆V
OUT
,
∆V
REF
= 1%.
(3) Bandwidth of 10 Hz to 10kHz.
(4) 120Hz input ripple.
(5) This device is ESD sensitive. Use of standard ESD handling precautions is required.
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SC1541
POWER MANAGEMENT
Pin Configurations
Ordering Information
Device
(1)(2)
SC1541CM-X.X.TR
SC1541CM-X.X.TRT
(3)
P ackag e
TO-263-5
SC1541CS-X.X.TR
SC1541CS-X.X.TRT
(3)
SO-8
SO-8
TO-263-5
PIN
1
2
3/TAB
4
5
FUNCTION
EN
GND
OUT
IN
NC
Notes:
(1) Where X.X denotes voltage options. Available
voltages are: 1.8V, 2.5V and 3.3V. Contact factory for
additional voltage options.
(2) Only available in tape and reel packaging. A reel
contains 800 (TO-263-5) or 2500 (SO-8) devices.
(3)
Halogen Free, and RoHS/WEEE compliant
.
Block Diagram
Pin Descriptions
Pin Name
EN
GND
NC
IN
OUT
SO-8 Pin #
1
2
4
3
5, 6, 7, 8
TO-263-5 Pin #
1
2
5
4
3/TAB
Pin Function
Active high enable for the regulator output. Connect to V
IN
if not being used.
Ground pin. Bottom end of the internal feedback resistor chain.
No connection.
This is the input supply pin for the device.
This is the power output of the device. This pin is electrically connected to
the tab of the TO-263-5 package.
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SC1541
POWER MANAGEMENT
Outline Drawing - SO-8
A
N
2X E/2
E1 E
1
ccc C
2X N/2 TIPS
2
e/2
B
D
aaa C
SEATING
PLANE
A2 A
C
bxN
bbb
A1
C A-B D
GAGE
PLANE
0.25
SEE DETAIL
SIDE VIEW
NOTES:
1.
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H-
3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
OR GATE BURRS.
4. REFERENCE JEDEC STD MS-012, VARIATION AA.
e
D
DIM
A
A1
A2
b
c
D
E1
E
e
h
L
L1
N
01
aaa
bbb
ccc
DIMENSIONS
MILLIMETERS
INCHES
MIN NOM MAX MIN NOM MAX
-
.053
.069
-
.004
.010
-
.049
.065
-
.012
.020
-
.007
.010
.189 .193 .197
.150 .154 .157
.236 BSC
.050 BSC
-
.010
.020
.016 .028 .041
(.041)
8
-
0°
8°
.004
.010
.008
-
1.35
1.75
-
0.10
0.25
-
1.25
1.65
-
0.31
0.51
-
0.17
0.25
4.80 4.90 5.00
3.80 3.90 4.00
6.00 BSC
1.27 BSC
-
0.25
0.50
0.40 0.72 1.04
(1.04)
8
-
0°
8°
0.10
0.25
0.20
h
h
H
c
A
L
(L1)
DETAIL
01
A
Land Pattern - SO-8
(1)
X
DIM
(C)
G
Z
C
G
P
X
Y
Z
DIMENSIONS
INCHES
MILLIMETERS
(.205)
.118
.050
.024
.087
.291
(5.20)
3.00
1.27
0.60
2.20
7.40
Y
P
NOTES:
1.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
2. REFERENCE IPC-SM-782A, RLP NO. 300A.
Note:
(1) More copper area should be used to lower R
TH(J-A)
as needed.
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