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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