28
LTC1709-8/LTC1709-9
PART NUMBER DESCRIPTION COMMENTS
LTC1438/LTC1439 Dual High Efficiency Low Noise Synchronous Step-Down Switching Regulators POR, Auxiliary Regulator
LTC1538-AUX Dual High Efficiency Low Noise Synchronous Step-Down Switching Regulator Auxiliary Regulator, 5V Standby
LTC1436A-PLL High Efficiency Low Noise Synchronous Step-Down Switching Regulator Adaptive Power
TM
Mode, 24-Pin SSOP
LTC1628/LTC1628-PG Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators Constant Frequency, Standby, 5V and 3.3V LDOs
LTC1629/LTC1629-PG PolyPhase High Efficiency Controllers Expandable Up to 12 Phases, G-28, Up to 120A
LTC1929/LTC1929-PG 2-Phase High Efficiency Controllers Adjustable Output Up to 40A, G-28
LTC1702/LTC1703 Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators 500kHz, 25MHz GBW
LTC1708-PG Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator 1.3V ≤ V
OUT
≤ 3.5V, Current Mode Ensures
with 5-Bit VID and Power Good Indication Accurate Current Sharing, 3.5V ≤ V
IN
≤ 36V
LTC1709 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator 1.3V ≤ V
OUT
≤ 3.5V, Current Mode Ensures
with 5-Bit VID and Fault Coupling Control Accurate Current Sharing, 3.5V ≤ V
IN
≤ 36V
LTC1709-7 High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator 0.9V ≤ V
OUT
≤ 2V, Current Mode Ensures
with 5-Bit Mobile VID, and Three Low-Current Modes Accurate Current Sharing, 3.5V ≤ V
IN
≤ 36V
LTC1735 High Efficiency Synchronous Step-Down Controller Burst Mode
TM
Operation, 16-Pin Narrow SSOP,
Fault Protection, 3.5V ≤ V
IN
≤ 36V
LTC1736 High Efficiency Synchronous Step-Down Controller with 5-Bit VID Output Fault Protection, Power Good, GN-24,
3.5V ≤ V
IN
≤ 36V, 0.925V ≤ V
OUT
≤ 2V
Adaptive Power and Burst Mode are trademarks of Linear Technology Corporation.
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 2000
170989f LT/LCG 0900 4K • PRINTED IN USA
TYPICAL APPLICATIO
U
RELATED PARTS
Figure 12. 1.3V to 3.5V/20A CPU Power Supply with Active Voltage Positioning
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
RUNN/SS
SENSE1
+
SENSE1
–
EAIN
PLLFLTR
PLLIN
NC
I
TH
SGND
V
DIFFOUT
V
OS
–
V
OS
+
SENSE2
–
SENSE2
+
ATTENOUT
ATTENIN
VID0
VID1
NC
TG1
SW1
BOOST1
V
IN
BG1
EXTV
CC
INTV
CC
PGND
BG2
BOOST2
SW2
TG2
PGOOD
V
BIAS
VID4
VID3
VID2
1000pF
0.22µF
LTC1709-8
M1 M2
D1
MBRS140T3
D2
MBRS140T3
V
IN
5V TO 28V
V
OUT
1.3V TO 3.5V
20A
SWITCHING FREQUENCY = 200kHz
C
IN
: 5A RIPPLE CURRENT RATING REQUIRED
C
OUT
: 4 × 180µF/4V PANASONIC SP
L1 TO L2: 1.5µH SUMIDA CEP125-1R5MC
M1 TO M4: FAIRCHILD FDS7760A
OR Siliconix Si4430
10µF
0.1µF
5V (OPT)
470pF
VID INPUTS
1000pF
100pF
680pF
INTV
CC
0.1µF
6.8k
15k
10k
2.7k
51k
0.22µF
0.1µF
PGOOD
10Ω
100k
10Ω
C
IN
47µF 35V
0.004Ω
0.004Ω
M3
L2
M4
170989 F12
C
OUT
+
+
L1
