Liteon Semiconductor Corporation
LSP2159
1.5A Low Voltage Low Dropout CMOS Regulator
FEATURES
Output Voltage Available in 1.8V, 2.5V, 3.3V
Stable with a Ceramic Output Capacitor of
4.7uF or Higher
Maximum Dropout Voltage: 650mV at 3.3V
Typical low Quiescent Current 100uA
Over Temperature Shutdown
Short Circuit Protection
Low Temperature Coefficient
Standard SOT223-3L, TO252-3L and
TO263-3L Packages.
GENERAL DESCRIPTION
The LSP2159 is a 1.5A CMOS LDO regulator that
features a low quiescent current, ultra low input, output
and dropout voltages, as well as over temperature
shutdown. It is available in SOT223-3L, TO252-3L and
TO263-3L packages. The fixed output voltage of the
LSP2159 is set at the factory and trimmed to ±2%. The
LSP2159 is stable with a ceramic output capacitor of
4.7uF or higher.
This family of regulators can provide either a
stand-alone power supply solution or act as a post
regulator for switch mode power supplies. They are
particularly well suited for applications requiring low
input and output voltage.
APPLICATIONS
SATA Power Supply
LCD TV/ Monitors
Wireless Devices
Communication Devices
Portable Electronics
Post Regulator for SMPS
PIN CONFIGURATION
TO252-3L
(Top View)
TO263-3L
(Top View)
SOT223-3L
(Top View)
3
2
1
Tab is Pin 2
3
2
1
Tab is Pin 2
Tab is Pin 2
3
2
1
PIN DESCRIPTION
Pin Number
SOT223-3L
TO252-3L
TO263-3L
1
2,TAB
3
SOT223-3L B type
TO252-3L B type
TO263-3L B type
3
1
2,TAB
Pin Name
VIN
GND
VOUT
Pin Function
Input
Ground
Output
Please be aware that an
Important Notice
concerning availability, disclaimers, and use in critical
applications of LSC products is at the end of this document.
1/14
Rev1.8
Liteon Semiconductor Corporation
LSP2159
1.5A Low Voltage Low Dropout CMOS Regulator
BLOCK DIAGRAM
TYPICAL APPLICATIONS CIRCUITS
LSP2159
V
OUT
GND
C1
1µF
C2
4.7µF
V
IN
V
IN
V
OUT
ABSOLUTE MAXIMUM RATINGS
Parameter
Input Supply Voltage, EN Pin Voltage
Maximum Output Current
Output Pin Voltage
Internal Power Dissipation
SOT223-3L
TO252-3L
TO263-3L
SOT223-3L
TO252-3L
TO263-3L
SOT223-3L
TO252-3L
TO263-3L
Rating
+6
PD/(VIN-VO)
-0.3 to VIN+0.3
625
1200
1600
7
7
2.7
160
90
45
-40 to 85
-40 to 125
-65 to 150
150
Unit
V
V
mW
Junction to Case Thermal Resistance (θ
JC
)
℃
/ W
Junction to Ambient Thermal Resistance (θ
JA
)
Operating temperature
Operating Junction Temperature
Storage Temperature
Maximum Junction Temperature
℃
/ W
°C
°C
°C
°C
Lead Temperature (Soldering, 5 sec)
300
°C
Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings
for prolonged time periods may affect device reliability
.
All voltages are with respect to ground.
2/14
Rev1.8
Liteon Semiconductor Corporation
LSP2159
1.5A Low Voltage Low Dropout CMOS Regulator
RECOMMENDED OPERATING CONDITIONS
Parameter
Input Supply Voltage
Operating temperature
Operating Junction Temperature
Rating
5.5
-40 to 85
-40 to 125
Unit
V
°C
°C
(V
IN
= V
OUT
+ 0.5V, C
IN
= 1µF, C
O
= 4.7µF, T
A
= 25
°
C unless otherwise specified.)
PARAMETER
Input Voltage
Output Voltage Accuracy
Short Circuit Current
Ground Current
Quiescent Current
Current Limit
Line Regulation
Load Regulation
Temperature Coefficient
Over Temperature Shutdown
Over Temperature Hystersis
Power Supply Ripple Rejection
SYMBOL
V
IN
V
O
I
SC
I
GND
I
Q
I
LIM
LNR
LDR
T
C
OTS
OTH
PSRR
TEST CONDITIONS
I
O
= 100mA
V
O
<
0.3V
I
O
= 1mA to 1.5A
I
O
= 0mA, V
IN
=5V, Io=0mA
I
O
= 10mA, V
O
≤
2.5V
V
IN
=V
O
+ 0.5V to V
O
+ 1.5V
I
O
= 10mA, V
O
＞2.5V
V
IN
= 3.3V to 5.5V
I
O
= 1mA to 1.5A
MIN
Note1
-2
TYP
MAX
5.5
+2
1.0
600
150
2
1
%/V
0.5
0.5
30
150
30
65
55
35
1000
450
300
40
1
2
%/A
ppm/°C
°C
°C
dB
1350
800
650
UNIT
V
%
A
µA
µA
A
ELECTRICAL CHARACTERISTICS
100
0.5
I
O
= 100mA
V
o
=1.5V
Dropout Voltage
Output Noise
V
DROP
V
n
f=100Hz
f= 1KHz
f= 10KHz
V
O
=1.8V
I
O
= 1.5A
V
O
=2.5V
V
O
=3.3V
f = 10Hz to 100kHz
mV
µV
RMS
Note 1：The minimum input voltage of the LSP2159 is determined by output voltage and dropout voltage. The
minimum input voltage is defined as:
V
IN(MIN)
=V
O
+V
DROP
APPLICATION INFORMATION
The LSP2159 families of low-dropout (LDO) regulators have several features that allow them to apply to a wide
range of applications. The 1.5A output current make the LSP2159 family suitable for powering many
microprocessors and FPGA supplies. The LSP2159 family also has low output noise (typically 40µVRMS with 4.7µF
output capacitor), making it ideal for use in telecom equipment.
External Capacitor Requirements
A 4.7µF or larger ceramic input bypass capacitor, connected between VIN and GND and located close to the
LSP2159, is required for stability. A 1.0uF minimum value capacitor from VO to GND is also required. To improve
transient response, noise rejection, and ripple rejection.
3/14
Rev1.8
Liteon Semiconductor Corporation
LSP2159
1.5A Low Voltage Low Dropout CMOS Regulator
(1) 1 uF Capacitor for input
(2) 4.7uF Capacitor for output
Regulator Protection
The LSP2159 features internal current limiting, thermal protection and short circuit protection. During normal
operation, the LSP2159 limits output current to about 2A. When current limiting engages, the output voltage scales
back linearly until the over current condition ends. While current limiting is designed to prevent gross device failure,
care should be taken not to exceed the power dissipation ratings of the package. If the temperature of the device
exceeds 150°C, thermal-protection circuitry will shut down. Once the device has cooled down to approximately 30°C
below the high temp trip point, regulator operation resumes. The short circuit current of the LSP2159 is about 1A
when its output pin is shorted to ground.
Thermal Information
The amount of heat that an LDO linear regulator generates is:
P
D
=(V
IN
-V
O
)I
O
.
All integrated circuits have a maximum allowable junction temperature (T
J
max) above which normal operation is not
assured. A system designer must design the operating environment so that the operating junction temperature (T
J
)
does not exceed the maximum junction temperature (T
J
max). The two main environmental variables that a designer
can use to improve thermal performance are air flow and external heatsinks. The purpose of this information is to aid
the designer in determining the proper operating environment for a linear regulator that is operating at a specific
power level.
In general, the maximum expected power (P
D(max)
) consumed by a linear regulator is computed as:
P
D( MAX)
=
V
I( avg)
−
V
O (avg )
I
O (avg)
+
V
I( avg)
I
( Q)
Where:
V
I (avg)
is the average input voltage.
V
O(avg)
is the average output voltage.
I
O(avg)
is the average output current.
I
(Q)
is the quiescent current.
For most LDO regulators, the quiescent current is insignificant compared to the average output current; therefore,
the term V
I(avg)
xI
(Q)
can be neglected. The operating junction temperature is computed by adding the ambient
temperature (T
A
) and the increase in temperature due to the regulator's power dissipation. The temperature rise is
computed by multiplying the maximum expected power dissipation by the sum of the thermal resistances between
the junction and the case (R
θJC
), the case to heatsink (R
θCS
), and the heatsink to ambient (R
θSA
). Thermal
resistances are measures of how effectively an object dissipates heat. Typically, the larger the devices, the more
surface area available for power dissipation so that the object’s thermal resistance will be lower.
This LSP2159 contains an internal thermal limiting circuit that is designed to protect the regulator in the event that
the maximum junction temperature is exceeded. When activated, typically at 150°C, the regulator output switches
off and then back on as the die cools.
The junction temperature can expresses as follow:
4/14
Rev1.8
(
)
Liteon Semiconductor Corporation
LSP2159
1.5A Low Voltage Low Dropout CMOS Regulator
T
J
= T
A
+ (θ
JA
×P
D
)
T
J
= Die junction temperature.
T
A
= Ambient temperature in the vicinity device.
P
D
= Total power dissipation (in watts).
θ
JA
= Thermal resistance junction-to-ambient
For example:
V
IN
-=5V, V
OUT
=3.3V, I
OUT
=1A, T
A
=25°C, Package=TO-252.
The power dissipation of LSP2159 can calculated from following equation:
P
D
=(V
IN
-V
OUT
)×I
OUT
+V
IN
×I
Q
Because I
Q
<< I
OUT
, the equation can simple as:
P
D
=(V
IN
-V
OUT
)×I
OUT
P
D
=(5-3.3) ×1=1.7 W
If the PC board area is 15×15 mm
2,
with 1 oz copper, double layer. The thermal resistance
θ
JA
is about 52°C/W
from thermal resistance figure.
T
J
= 25+ (52×1.7) =113.4°C. (< T
J(max)
=150°C)
In this case, the junction temperature is lower than the maximum rating, and this ensure a reliable operation.
θJA
(°C/W) vs. Cooper Area (TO-252)
θ
JA THERMAL RESISTANCE
100
θJA
(°C/W) vs. Cooper Area (SOT-223)
JUNCTION-TO-AIR (°C/W)
L
90
1 oz. Copper,
Double layer.
θJA
THERMAL RESISTANCE
JUNCTION-TO-AIR (°C/W)
160
140
80
70
60
50
40
0
5
10
15
20
L
LSP2159
120
100
1 oz. Copper,
Double layer.
80
60
25
30
35
40
0
5
10
15
20
25
30
35
40
L, LENTTH OF COPPER (mm)
L, LENTTH OF COPPER (mm)
5/14
Rev1.8
微控制器 MCU
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