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High efficiency "Green" Computer Systems
ADJ OR FIXED
SENSE
Now Available in Lead Free Packaging
DESCRIPTION
The SPX1582 is a 3A Low Dropout Regulator with extremely low dropout voltage. The adjustable version requires only
two external resistors to set the output voltage. The fixed version has a preset output of 3.3V, 2.8V or 2.5V and does
not require any external resistors. The SPX1582 features a low dropout of 400mV(Typ.) and offers fast transient
response. This device is suitable for Pentium applications requiring 2.8V, 2.5V from 3.3V ATX power supplies, where
low current input voltage 1V greater than the output voltage is needed. With an external sense pin the load regulation
is less than 1mV. This device is an excellent choice for the use in powering low voltage microprocessors that require
a lower dropout, fast transient response to regulate from 3.3V and 5V supplies. The SPX1582 is also an excellent choice
as a post regulator for switching supply applications.
The SPX1582 offers protection against over-current faults, reversed input polarity, over temperature operation and
positive or negative transient voltages.
The SPX1582 is offered in a 5 pin TO-220 and TO-263 compatible with industry standard 5-terminal regulators. For
5A, 3A and 1.5A ultra low dropout versions refer to SPX1581, SPX1582 and SPX1583 data sheets respectively.
TYPICAL APPLICATIONS CIRCUIT
3.3V
V
IN
5V
V
CTRL
V
IN
C1
330渭F
V
CTRL
5
SPX1582
4
2
ADJ
C2
10渭F
C3
.033渭F
R2
124惟
1
SENSE
R1
124惟
C4
2x330渭F
5V
V
CTRL
3
V
OUT
2.5V
V
OUT
3.3V
V
IN
V
IN
C1
330渭F
V
CTRL
5
SPX1582
4
2
3
1
V
OUT
V
CNTRL
V
OUT
V
IN
2.5V
V
OUT
SENSE
GND
C2
10渭F
C4
2x330渭F
(1) V
CTRL
needed when V
IN
< 5V.
(2) V
OUT
= V
REF
(1+R
2
/R
1
)+I
ADJ
R
2
.
(3) V
REF
is measured across adjust to sense.
(1) V
CTRL
needed when V
IN
< 5V.
Adjustable Regulator
Typical Fixed Regulator
Jun 17-06 Rev F
SPX1582 3A Ultra Low Dropout Voltage Regulator
漏 2006 Sipex Corporation
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