LT1587-1.5
Fixed 1.5V, 3A
Low Dropout
Fast Response
GTL+ Regulator
FEATURES
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DESCRIPTION
The LT
®
1587-1.5 is a low dropout 3-terminal regulator
with a fixed 1.5V output voltage and 3A output current
capability. The design is optimized for low voltage applica-
tions where transient response and minimum input voltage
are critical. Similar to the LT1085, it has lower dropout and
faster transient response. These improvements make it
ideal for low voltage microprocessor applications, espe-
cially as the regulator in an Intel Pentium Pro processor
GTL+ supply.
Current limit is trimmed to ensure specified output current
and controlled short-circuit current. On-chip thermal lim-
iting provides protection against any combination of over-
load that creates excessive junction temperatures.
The LT1587-1.5 is available in both the through-hole and
surface mount versions of the industry standard 3-pin
TO-220 power package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Pentium is a registered trademark of Intel Corporation
Fast Transient Response
Guaranteed Dropout Voltage at Multiple Currents
Load Regulation: 0.05% Typ
Trimmed Current Limit
On-Chip Thermal Limiting
APPLICATIONS
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Intel Pentium
®
Pro Processor GTL+ Supply
Low Voltage Logic Supplies
Battery-Powered Circuitry
TYPICAL APPLICATION
Intel Pentium Pro Processor GTL+ Supply
3.3V
LT1587-1.5
V
IN
V
OUT
GND
V
TT
= 1.5V
3A
C4 TO
C6
1µF
R1
75Ω
R2
150Ω
R5
100Ω
C13
0.1µF
R7
100Ω
R8
100Ω
R6
100Ω
V
REF
C14
0.1µF
R3
75Ω
R4
150Ω
V
TT
= 1.5V
3A
LT1587-1.5
V
OUT
V
IN
GND
C10 TO C12
1µF
3.3V
+
C1
100µF
10V
AVX TPS
+
C2, C3
100µF
10V
AVX TPS
V
REF
RX
TX
Q1
Q2
RX
RX
NOTE: LTC RECOMMENDS SEPARATE
V
TT
GENERATORS AT EACH BUS END
TO ENSURE CURRENT SHARING
BETWEEN THE REGULATORS AND TO
MINIMIZE V
TT
DISTRIBUTION DROPS
LT1587 • TA01
TX
Q3
•
•
•
Q4
TX
142 TOTAL SIGNAL LINES
U
U
U
+
C8, C9
100µF
10V
AVX TPS
+
C7
100µF
10V
AVX TPS
RX
TX
1
LINER [ LINEAR TECHNOLOGY ]
