28

LTC1709

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

©LINEAR TECHNOLOGY CORPORATION 1999

1709f LT/TP 0500 4K • PRINTED IN USA

TYPICAL APPLICATIO

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LTC1438/LTC1439

Dual High Efficiency Low Noise Synchronous Step-Down Switching Regulators POR, Auxiliary Regulator

LTC1438-ADJ

Dual Synchronous Controller with Auxiliary Regulator

POR, External Feedback Divider

LTC1538-AUX

Dual High Efficiency Low Noise Synchronous Step-Down Switching Regulator

Auxiliary Regulator, 5V Standby

LTC1539

Dual High Efficiency Low Noise Synchronous Step-Down Switching Regulator

5V Standby, POR, Low-Battery, Aux Regulator

LTC1436A-PLL

High Efficiency Low Noise Synchronous Step-Down Switching Regulator

Adaptive Power

LTC1628/LTC1628-PG Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator

Constant Frequency, Standby, 5V and 3.3V LDOs

LTC1629/LTC1629-PG PolyPhase High Efficiency Controller

Expandable Up to 12 Phases, G-28, Up to 120A

LTC1929

2-Phase High Efficiency Controller

Adjustable Output Up to 40A, G-28

LTC1702/LTC1703

Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator

500kHz, 25MHz GBW

LTC1709-7/

High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator with

1.3V

LTC1709-8/

5-Bit VID and Power Good Indication

1.1V

LTC1709-9

Current Mode Ensures Accurate Current Sharing,

3.5V

LTC1708-PG

Dual High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator

1.3V

with 5-Bit VID and Power Good Indication

Accurate Current Sharing, 3.5V

LTC1735

High Efficiency Synchronous Step-Down Controller

Burst Mode

Fault Protection, 3.5V

LTC1736

High Efficiency Synchronous Step-Down Controller with 5-Bit VID

Output Fault Protection, Power Good, GN-24,

3.5V

Adaptive Power and Burst Mode are trademarks of Linear Technology Corporation.

Figure 12. 5V Input, 1.8V/20A Power Supply with Active Voltage Positioning

SWITCHING FREQUENCY = 310kHz

MI – M4: FAIRCHILD FDS7760A

L1 – L2: SUMIDA CEP125-1R5M

D3, D4: CENTRAL CMDSH-3TR

36

35

34

33

32

31

30

29

28

27

26

25

24

23

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

NC

TG1

SW1

BOOST 1

BG1

PGND

BG2

BOOST 2

SW2

TG2

AMPMD

RUN/SS

EAIN

PLLFLTR

PLLIN

NC

SGND

–

+

LTC1709

M4

M3

0.1

µF

47k

15k

10k

51k

2.7k

22

ATTENOUT

21

16

VID4

ATTENIN

20

17

VID3

VID0

19

VID INPUTS

18

VID2

VID1

1000pF

1000pF

3.3nF

470pF

100pF

47

µF×2

GND

35V

M2

M1

D1

MBRM

140T3

D2

MBRM

140T3

0.22

µF

0.1

µF

4.7

µF

6.3V

0.1

µF

1

µF,25V

10

Ω

10

Ω

0.22

µF

D3

D4

4

×180µF

4V

1.3V TO 3.5V

5V TO 28V

L1

0.004

Ω

L2

1.5

µH

1.5

µH

0.004

Ω

1709 TA02