LT1587-1.5 Datasheet, PDF (1/8 Pages) Linear Technology – Fixed 1.5V, 3A Low Dropout Fast Response GTL+ Regulator

FEATURES
s _{Fast Transient Response}
s _{Guaranteed Dropout Voltage at Multiple Currents}
s _{Load Regulation: 0.05% Typ}
s _{Trimmed Current Limit}
s _{On-Chip Thermal Limiting}
U
APPLICATIONS
s _{Intel Pentium}^® _{Pro Processor GTL+ Supply}
s _{Low Voltage Logic Supplies}
s _{Battery-Powered Circuitry}
LT1587-1.5
Fixed 1.5V, 3A
Low Dropout
Fast Response
GTL+ Regulator
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
TYPICAL APPLICATION
Intel Pentium Pro Processor GTL+ Supply
3.3V
+
LT1587-1.5
V_IN
V_OUT
GND
V_TT = 1.5V
3A
C1
100µF
10V
AVX TPS
+
C2, C3
100µF
10V
AVX TPS
C4 TO
C6
1µF
R1
75Ω _VREF
R2
150Ω
C13
0.1µF
R5 R7
100Ω 100Ω
R8
100Ω
R6
100Ω
V_REF
R3
75Ω
C14 _R4
0.1µF _150Ω
V_TT = 1.5V
3A
C10 TO C12
1µF
LT1587-1.5
V_OUT
V_IN
GND
C8, C9
+
100µF
10V
AVX TPS
3.3V
C7
100µF
10V
AVX TPS
RX
TX
Q1
RX
Q2
TX
RX
RX
NOTE: LTC RECOMMENDS SEPARATE
TX
Q3
Q4
TX
V_TT GENERATORS AT EACH BUS END
TO ENSURE CURRENT SHARING
•
BETWEEN THE REGULATORS AND TO
•
MINIMIZE V_TT DISTRIBUTION DROPS
•
142 TOTAL SIGNAL LINES
LT1587 • TA01
1