Datasheet

12
LT1581/LT1581-2.5
 LINEAR TECHNOLOGY CORPORATION 1996
TYPICAL APPLICATION
U
Dual Regulators Power Pentium Processor or Upgrade CPU
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LTC
®
1430 High Power Synchronous Step-Down Switching Regulator >90% Efficiency High Current Microprocessor Supply
LTC1435 High Current Synchronous Step-Down Controller >90% Efficiency in 12V to 3.3V Applications
LT1575/LT1577 Single and Dual Low Dropout Regulator Controllers Fast Transient Response, No Bulk Capacitors Needed
LT1580 7A Fast Transient Response Regulator with 0.7V Dropout For 3.3V to 2.XXV Applications
LT1584 7A Low Dropout Fast Transient Response Regulator For High Performance Microprocessors
LT1585 4.6A Low Dropout Fast Transient Response Regulator For High Performance Microprocessors
C1
220µF
10V
C3
220µF
10V
C10
1µF
C9
220µF
10V
C2
220µF
10V
C5
0.33µF
C11
22µF
35V
LT1587
ADJ
V
IN
V
OUT
–
+
I/O
SUPPLY
3.5V/3.3V
C8
0.1µF
C4
0.33µF
C6
0.01µF
R3
110Ω
1%
R11
10k
R2
470Ω
R14, 2Ω
R13
0.005Ω*
R8
107Ω
0.35%
R12
0.0075Ω*
D1
1N4148
D2
1N4148
R4
178Ω
1%
R1
10k
5V
5V
12V
R10
10k
R7
107Ω
0.25%
R5
10k
E3
TO CPU
VOLTAGE
SELECT PIN
5V
R9
10k
R6
89.8Ω
0.5%
Q1
ZVN4206
Q2
2N3904
Q3
2N7002
1581 TA04
12V
3
4
1
CORE
SUPPLY
3.5V/2.5V
LT1006
C7
330µF
6.3V
LT1581
6
5
V
CONT
V
POWER
SENSE
V
OUT
ADJ
*RESISTORS ARE IMPLEMENTED AS COPPER TRACES ON PCB 
IF 1 OZ COPPER, TRACE WIDTHS ARE 0.05 INCH
IF 2 OZ COPPER, TRACE WIDTHS ARE 0.025 INCH
R13 IS 0.83 INCHES LONG, R12 IS 1.24 INCHES LONG
E3
0
1
CPU TYPE
P55C
P54C
+
+
+
+
+
+
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone]
●
FAX: [phone]
●
www.linear-tech.com
158125fa LT/TP 0399 2K REV A • PRINTED IN USA