View L1581_238500.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

NIKO-SEM
Dual Input Ultra Low Dropout Voltage Regulator (ULDO)
FEATURES
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.
Low dropout voltage 600mV at rated load current Remote sense operation Fast transient response 0.5% voltage reference initial accuracy Standard 5 terminal, Low cost TO-252 packages
APPLICATIONS
3.3V to 2.8V or 2.5V for Motherboards or VGA Card Spilt plane microprocessor supplies Post regulator for switching supplies
TYPICAL APPLICATION
Adjustable Output Parts(2)
L1581X Vin Vctrl 5 4 Vin ADJ CTR'L OUT SENSE 3 1 Vout
2
Vref R1 C1 330uF C2 10uF C3 0.033uF R2 Iadj C4 330uF
Vo = Vref (1+R2/R1) + Iadj x R2
1
OCT-11-Y02
NIKO-SEM
Fixed Output Parts
Dual Input Ultra Low Dropout Voltage Regulator (ULDO)
L1581 Series
TO-252
L1581X-2.5 Vin Vctrl C1 330uF C2 10uF 5 4 Vin ADJ CTR'L OUT SENSE 3 2.5V Vout 1 C4 330uF
L1581X-3.3 Vin Vctrl C1 330uF C2 10uF 5 4 Vin ADJ CTR'L OUT SENSE 3 3.3V Vout 1 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
2
2
OCT-11-Y02
NIKO-SEM
Dual Input Ultra Low Dropout Voltage Regulator (ULDO)
L1581 Series
TO-252
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage, VIN Control Input Voltage, VCTRL Power Dissipation, PD Thermal Resistance Junction to Case, JC Thermal Resistance Junction to Ambient, JA 7V 13.2V Internally Limited 3 C/W 60 C/W Operating Junction Temperature Range, TJ Storage Temperature Range, TSTG 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 Reference Voltage(1) (Adj. Voltage Versions) Dropout Voltage(1) (2) Minimum VIN Output Voltage(1) (Fixed Voltage Versions) Line Regulation(1) Load Regulation Symbol VREF Test Conditions VCTRL=4.5V, VIN=2.05V, IOUT=10mA VCTRL = 4.5V, 10mA < IOUT < 5A, VIN = 2.05V 1.25V 0.54V Typical Limits 1.237V~1.263V 1.231V~1.269V 0.62V (Max) 1% VOUT 1.5% 1.0mV 1.0mV 0.002 %/W
Minimum Load (4) Current
VI - VO VCTRL = 4.75V, IOUT = 5A VCTRL = 5V, VIN = VOUT 0.8V, IOUT=10mA VCTRL = 5V, 10mA < IOUT < 5A, VIN = VOUT 0.8V
VOUT
REG(LINE) VCTRL = 4.5V to 12V, VIN = (VOUT 0.8V) to 5.5V, IOUT = 10mA REG(LOAD) VCTRL = 4.5V, VIN = (VOUT0.8V) , IOUT = 10mA ~ 5A
3.0mV 5.0mV 0.02% / W 10mA 120A 120mA 5.1A (Min)
Thermal Regulation(6) REG(Thermal) 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 VOUT = 100mV
5mA 50A 33mA
Adjust Pin Current Control Pin Current(3) Current Limit
3
OCT-11-Y02
NIKO-SEM
Ripple Rejection Ratio(5) NOTE :
Dual Input Ultra Low Dropout Voltage Regulator (ULDO)
RA VCTRL = VIN = 5V, IOUT = 5A 80dB
L1581 Series
TO-252
60dB (Min)
Low duty cycle pulse testing with Kelvin connections required. Minimum input to output voltage differential required to maintain 1% regulation. Current used to drive the output section. Required to maintain regulation. Resistor divider R1, R2 is usually utilized for minimum load current. VRIPPLE = 1VPK-PK, 120Hz. (6) 30ms.
(1) (2) (3) (4) (5)
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
NIKO-SEM
PIN FUNCTIONS
NO 1 2 3 4 FUNCTION Sense Adjust Output Control
Dual Input Ultra Low Dropout Voltage Regulator (ULDO)
L1581 Series
TO-252
DESCRIPTION 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. Transient response can be improved by adding a small bypass capacitor from the adjust pin to ground. 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 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 voltage on this pin must be between 0.1V and 0.7V greater than the output, depending upon load current (see dropout specifications).
5
Input
5
OCT-11-Y02
NIKO-SEM
Dual Input Ultra Low Dropout Voltage Regulator (ULDO) TO-252 (DPAK) MECHANICAL DATA
mm
L1581 Series
TO-252
Dimension A B C D E F G
Min. 2.19 0.46 0.89 0.46 0.00 3.04
Typ. 9.7
Max. 2.38 0.58 1.27 0.53 0.13 5.33
Dimension H I J K L M N
mm Min. 0.89 6.35 5.21 0.64 1.27BSC Typ. Max. 2.03 6.73 5.46 0.89
12
34
5
6
OCT-11-Y02

▲Up To Search▲

Price & Availability of L1581

	To Download L1581 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .