lt1528ct-pbf

Manufacturer Part Numberlt1528ct-pbf
Description3a Low Dropout Regulator For Microprocessor Applications
ManufacturerLinear Technology Corporation
lt1528ct-pbf datasheet
 


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FEATURES
Dropout Voltage: 0.6V at I
= 3A
OUT
Fast Transient Response
Output Current: 3A
Quiescent Current: 400 A
No Protection Diodes Needed
Fixed Output Voltage: 3.3V
Controlled Quiescent Current in Dropout
Shutdown I
= 125 A
Q
Stable with 3.3 F Output Capacitor
Reverse Battery Protection
No Reverse Output Current
Thermal Limiting
U
APPLICATIO S
Microprocessor Applications
Post Regulator for Switching Supplies
5V to 3.3V Logic Regulator
U
TYPICAL APPLICATIO
Microprocessor Supply with Shutdown
5
1
IN
OUT
V
=5V
LT1528
IN
4
2
SHDN
SENSE
GND
3
V
(PIN 4)
OUTPUT
SHORTING
SHDN
<0.25
OFF
J1
>2.80
ON
J2
NC
ON
J3
3A Low Dropout Regulator
for Microprocessor Applications
DESCRIPTIO
®
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 capaci-
tor ESR. Dropout voltage is 75mV at 10mA, rising to
300mV at 1A and 600mV at 3A. The device has a quiescent
current of 400 A. Quiescent current is well controlled; it
does not increase significantly as the device enters drop-
out. The regulator can operate with output capacitors as
small as 3.3 F, although larger capacitors will be needed
to achieve the performance required in most microproces-
sor applications. The LT1528 is available with a fixed
output voltage of 3.3V. An external SENSE pin allows
adjustment to output voltages greater than 3.3V, using a
simple resistive 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 125 A in shutdown. The LT1528 is
available in 5-lead TO-220 and 5-lead DD packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
V
OUT
+
4 47 F*
15
68
SOLID TANTALUM
J1
J2
J3
330
*CHOOSE CAPACITORS
V
OUT
TO MEET PROCESSOR
3.30
REQUIREMENTS
3.45
4.00
LT1528 • TA01
LT1528
U
Dropout Voltage
0.6
0.5
0.4
0.3
0.2
0.1
0
0
0.5
1.0
1.5
2.0
2.5
3.0
OUTPUT CURRENT (mA)
LT1528 • TA02
1528fa
1

lt1528ct-pbf Summary of contents

  • Page 1

    ... Intel, IBM, AMD, and Cyrix. The LT1528 has both reverse input and reverse output protection and includes a shutdown feature. Quiescent current drops to 125 A in shutdown. The LT1528 is available in 5-lead TO-220 and 5-lead DD packages. , LTC and LT are registered trademarks of Linear Technology Corporation. V OUT + ...

  • Page 2

    ... LOAD I = 100mA LOAD I = 700mA LOAD I = 700mA LOAD I = 1.5A LOAD I = 1.5A LOAD LOAD LOAD ORDER PART NUMBER SHDN LT1528CT 3 GND 2 SENSE 1 OUTPUT = MIN TYP MAX UNITS 3.250 3.300 3.350 3.200 3.300 3.400 1 110 150 ...

  • Page 3

    ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T PARAMETER GND Pin Current (Note 6) SENSE Pin Current (Notes 4, 8) SHDN Threshold SHDN Pin Current (Note 9) Quiescent Current ...

  • Page 4

    LT1528 W U TYPICAL PERFOR A CE CHARACTERISTICS Guaranteed Dropout Voltage 1.0 = TEST POINTS 0.9 0.8 0.7 T 125 C J 0.6 0 0.4 0.3 0.2 0 0.5 1.0 1.5 2.0 2.5 3.0 ...

  • Page 5

    W U TYPICAL PERFOR A CE CHARACTERISTICS SHDN Pin Threshold (Off-to-On) 2.0 1 1.6 LOAD 1.4 1 1mA LOAD 1.0 0.8 0.6 0.4 0.2 0 –50 – 100 125 TEMPERATURE ( ...

  • Page 6

    LT1528 W U TYPICAL PERFOR A CE CHARACTERISTICS Ripple Rejection OUT SOLID TANTALUM OUT 30 SOLID TANTALUM 1.5A OUT ...

  • Page 7

    CTIO S SHDN (Pin 4): This pin is used to put the device into shutdown. In shutdown the output of the device is turned off. This pin is active low. The device will be shut ...

  • Page 8

    LT1528 U U APPLICATIO S I FOR ATIO The LT1528 is specified with the SENSE pin tied to the OUTPUT pin. This sets the output voltage to 3.3V. Speci- fications for output voltage greater than 3.3V will be proportional to ...

  • Page 9

    U U APPLICATIO S I FOR ATIO The maximum junction temperature will be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or 31 81.4 C JMAX Output ...

  • Page 10

    LT1528 U U APPLICATIO S I FOR ATIO The reverse output current will follow the curve in Figure 3 when the input is pulled to ground. This current flows through the OUTPUT pin to ground. The state of the SHDN ...

  • Page 11

    ... HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. U ...

  • Page 12

    ... MEASURED AT THE SEATING PLANE T5 (TO-220) 0399 COMMENTS >90% Efficient 1A 3.3V Conversion >90% Efficient High Current Microprocessor Supply 15 A Quiescent Current For High Performance Microprocessors For High Performance Microprocessors LT/TP 1201 1.5K REV A • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1995 1528fa ...