L1581D-3.3.pdf 데이터시트 (총 6 페이지) - 파일 다운로드 L1581D-3.3 데이타시트 다운로드

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NIKO-SEM
Dual Input Ultra Low Dropout
Voltage Regulator (ULDO)
L1581 Series
TO-252
GENERAL DESCRIPTION
The L1581 is a positive and very low
dropout voltage regulator with 5A output
current capability. When supplying 2.5V or
2.8V on Motherboards or VGA Card where
both 5V and 3.3V supplies are available,
the superior dropout characteristics of the
L1581 result in reduced heat dissipation
compared to regular LDOs, thus allowing
heat sink reduction. The adjustable version
requires only two external resistors to set
the output. The L1581 features a low
dropout of less than 600mV and offers fast
transient response, remote sense, internal
limiting, thermal shutdown and safe
operating area protection of the output
device.
The L1581 is a five terminal adjustable
voltage regulator available in the popular 5
pin TO-252 packages.
FEATURES
z Low dropout voltage 600mV at rated load
current
z Remote sense operation
z Fast transient response
z 0.5% voltage reference initial accuracy
z Standard 5 terminal, Low cost TO-252
packages
APPLICATIONS
z 3.3V to 2.8V or 2.5V for Motherboards or
VGA Card
z Spilt plane microprocessor supplies
z Post regulator for switching supplies
TYPICAL APPLICATION
Adjustable Output Parts(2)
Vin
Vctrl
C1
330uF
C2
10uF
L1581X
5 Vin
4 CTR'L
OUT 3
SENSE 1
Vref
R1
Iadj
C3
0.033uF
R2
Vout
C4
330uF
Vo = Vref (1+R2/R1) + Iadj x R2
1 OCT-11-Y02

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NIKO-SEM
Dual Input Ultra Low Dropout
Voltage Regulator (ULDO)
L1581 Series
TO-252
Fixed Output Parts
Vin
Vctrl
C1
330uF
C2
10uF
L1581X-2.5
5 Vin
OUT 3
4 CTR'L
SENSE 1
2.5V Vout
C4
330uF
Vin
Vctrl
C1
330uF
C2
10uF
L1581X-3.3
5 Vin
OUT 3
4 CTR'L
SENSE 1
3.3V Vout
C4
330uF
NOTES :
(1) If the same voltage is input to both INPUT and CONTROL, then the dropout voltage will become 1.3V
maximum.
(2) A small (~0.033uF) capacitor can be used to bypass the ADJUST pin to improve transient response, if needed.
(3) Capacitor values are for reference only. Good quality, low ESR tantalum or aluminum electrolytic capacitors
should be used. Increasing the value of the output capacitor will improve the overall transient response.
2 OCT-11-Y02

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NIKO-SEM
Dual Input Ultra Low Dropout
Voltage Regulator (ULDO)
L1581 Series
TO-252
ABSOLUTE MAXIMUM RATINGS
z Input Supply Voltage, VIN
Control Input Voltage, VCTRL
z Power Dissipation, PD
z Thermal Resistance
Junction to Case, θJC
z Thermal Resistance
Junction to Ambient, θJA
7V
13.2V
Internally
Limited
3 °C/W
60 °C/W
z Operating Junction
Temperature Range, TJ
z Storage Temperature
Range, TSTG
z Lead Temperature, TLEAD
(Soldering, 10 Seconds)
0 to 125 °C
-40 to 150 °C
260 °C
ELECTRICAL CHARACTERISTICS (Unless otherwise specified, Vout = Vsns , Vadj = 0V ,
Cctl = Cin= Cout =10 uF,TJ = 25 °C)
Parameter
Symbol
Test Conditions
Typical
Limits
Reference Voltage(1)
(Adj. Voltage
Versions)
Dropout Voltage(1) (2)
Minimum VIN
Output Voltage(1)
(Fixed Voltage
Versions)
Line Regulation(1)
Load Regulation
VREF
VI - VO
ŠVCTRL=4.5V, VIN=2.05V, IOUT=10mA
Š1.237V~1.263V
ŠVCTRL = 4.5V, 10mA < IOUT < 5A, 1.25V Š1.231V~1.269V
VIN = 2.05V
VCTRL = 4.75V, IOUT = 5A
0.54V 0.62V (Max)
VOUT
ŠVCTRL = 5V, VIN = VOUT 0.8V,
IOUT=10mA
ŠVCTRL = 5V, 10mA < IOUT < 5A,
VIN = VOUT 0.8V
REG(LINE)
VCTRL = 4.5V to 12V,
0.8V) to 5.5V, IOUT =
VIN = (VOUT
10mA
REG(LOAD)
VCTRL = 4.5V, VIN =
IOUT = 10mA ~ 5A
(VOUT0.8V)
,
VOUT
1.0mV
1.0mV
± 1%
± 1.5%
3.0mV
5.0mV
Thermal Regulation(6) REG(Thermal)
0.002 0.02% / W
Minimum Load
Current(4)
Adjust Pin Current
Control Pin Current(3)
Current Limit
IO
IADJ
ICTRL
ICL
VCTRL = 5V, VIN = VOUT0.8V
VCTRL = 4.5V, VIN = VOUT0.8V,
IOUT = 10mA
VCTRL = 4.5V, VIN = VOUT0.8V,
IOUT = 5A
VCTRL = 4.5V, VIN = VOUT0.8V
ΔVOUT = 100mV
%/W
5mA
50µA
33mA
10mA
120µA
120mA
5.1A (Min)
3 OCT-11-Y02

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NIKO-SEM
Dual Input Ultra Low Dropout
Voltage Regulator (ULDO)
L1581 Series
TO-252
Ripple Rejection
Ratio(5)
RA VCTRL = VIN = 5V, IOUT = 5A
80dB 60dB (Min)
NOTE :
(1) Low duty cycle pulse testing with Kelvin connections required.
(2) Minimum input to output voltage differential required to maintain 1% regulation.
(3) Current used to drive the output section.
(4) Required to maintain regulation. Resistor divider R1, R2 is usually utilized for minimum load current.
(5) VRIPPLE = 1VPK-PK, 120Hz.
(6) 30ms.
DEVICE SELECTION GUIDE
Device
Package
Marking
L1581D
TO-252
L1581D
L1581D-2.5 L1581D-3.3
TO-252
TO-252
L1581D-2.5 L1581D-3.3
PIN CONFIGURATIONS
1 2 34 5
Pin #
Function
1 Sense
2 Adjust
3 Output
4 Control
5 Input
Note: TAB is Output Pin
4 OCT-11-Y02

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NIKO-SEM
Dual Input Ultra Low Dropout
Voltage Regulator (ULDO)
L1581 Series
TO-252
PIN FUNCTIONS
NO FUNCTION
DESCRIPTION
1
Sense
This pin is the positive side of the reference voltage for the device. With
this pin it is possible to Kelvin sense the output voltage at the load.
This pin is the negative side of the reference voltage for the device.
2 Adjust Transient response can be improved by adding a small bypass capacitor
from the adjust pin to ground.
3
Output
This is the power output of the device, and is electrically connected to
the TAB.
This pin is the supply pin for the control circuitry for the device. The
4
Control
current flow into this pin will be approximately 1% of the output. For the
device to regulate, the voltage at this pin must be between 1.0V and
1.3V greater than the output voltage (see dropout specifications).
This is the collector input to the power device of the L1581. The output
load current is supplied through this pin. For the device to regulate, the
5 Input voltage on this pin must be between 0.1V and 0.7V greater than the
output, depending upon load current (see dropout specifications).
5 OCT-11-Y02