LT1528CQPBF

Manufacturer Part NumberLT1528CQPBF
DescriptionTO-263
ManufacturerLinear Technology Corporation
LT1528CQPBF datasheets
 

Specifications of LT1528CQPBF

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FEATURES
n
Dropout Voltage: 0.6V at I
= 3A
OUT
n
Fast Transient Response
n
Output Current: 3A
n
Quiescent Current: 400μA
n
No Protection Diodes Needed
n
Fixed Output Voltage: 3.3V
n
Controlled Quiescent Current in Dropout
n
Shutdown I
= 125μA
Q
n
Stable with 3.3μF Output Capacitor
n
Reverse Battery Protection
n
No Reverse Output Current
n
Thermal Limiting
APPLICATIONS
n
Microprocessor Applications
n
Post Regulator for Switching Supplies
n
5V to 3.3V Logic Regulator
TYPICAL APPLICATION
Microprocessor Supply with Shutdown
5
1
IN
OUT
V
=5V
LT1528
IN
J1
4
2
SHDN
SENSE
GND
330Ω
3
V
(PIN 4)
OUTPUT
SHORTING
V
SHDN
<0.25
OFF
J1
3.30
>2.80
ON
J2
3.45
NC
ON
J3
4.00
3A Low Dropout Regulator
for Microprocessor Applications
DESCRIPTION
The LT
®
1528 is a 3A low dropout regulator optimized to
handle the large load current transients associated with
the current generation of microprocessors. This device has
the fastest transient response of currently available PNP
regulators and is very tolerant of variations in capacitor
ESR. Dropout voltage is 75mV at 10mA, rising to 300mV
at 1A and 600mV at 3A. The device has a quiescent cur-
rent of 400μA. Quiescent current is well controlled; it does
not increase signifi cantly as the device enters dropout.
The regulator can operate with output capacitors as small
as 3.3μF, although larger capacitors will be needed to
achieve the performance required in most microprocessor
applications. The LT1528 is available with a fi xed output
voltage of 3.3V. An external SENSE pin allows adjustment
to output voltages greater than 3.3V, using a simple resis-
tive divider. This allows the device to be adjusted over a
wide range of output voltages, including the 3.3V to 4.2V
range required by a variety of processors from Intel, IBM,
AMD, and Cyrix.
The LT1528 has both reverse input and reverse output
protection and includes a shutdown feature. Quiescent
current drops to 125μA in shutdown. The LT1528 is avail-
able in 5-lead TO-220 and 5-lead DD-PAK packages.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
V
OUT
+
4 × 47μF*
15Ω
68Ω
SOLID TANTALUM
J2
J3
*CHOOSE CAPACITORS
OUT
TO MEET PROCESSOR
REQUIREMENTS
1528 TA01
LT1528
Dropout Voltage
0.6
0.5
0.4
0.3
0.2
0.1
0
0
1.0
1.5
2.0
2.5
3.0
0.5
OUTPUT CURRENT (mA)
1528 TA02
1528fb
1