LTC3371

1

3371fa

Typical applicaTion

FeaTures

DescripTion

4-Channel 8A Configurable

Buck DC/DCs with Watchdog

and Power-On Reset

TheLTC®3371isahighlyflexiblemultioutputpowersupply

IC. The device includes four synchronous buck convert-

ers, configured to share eight 1A power stages, each of

which is powered from independent 2.25V to 5.5V inputs.

The DC/DCs are assigned to one of eight possible power

configurations via pin programmable C1-C3 pins. The

common buck switching frequency may be programmed

withanexternalresistor,synchronizedtoanexternaloscil-

lator, or set to a default internal 2MHz clock. The operating

mode for all DC/DCs may be programmed for Burst Mode

or forced continuous mode operation.

The CT pin programs the timing parameters of four inde-

pendent RST pins as well as the watchdog timer.

To reduce input noise, the buck converters are phased in

90° steps. Precision enable pin thresholds facilitate reli-

able power sequencing. The LTC3371 is available in low

profile 38-lead 5mm

× 7mm QFN and TSSOP packages.

applicaTions

n

8

× 1A Buck Power Stages Configurable as 2, 3 or 4

Output Channels

n

8 Unique Output Configurations (1A to 4A Per Channel)

n

n

Low Total No Load Supply Current:

n

15µA In Shutdown (All Channels Off)

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18µA Per Additional Channel

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Precision Enable Pin Thresholds for Autonomous

Sequencing

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1MHz to 3MHz RT Programmable Frequency

(2MHz Default) or PLL Synchronization

n

Temp Monitor Indicates Die Temperature

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CT Programmed Watchdog Timer

n

Independent RST Pins Indicate Buck in Regulation

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Thermally Enhanced 38-Lead 5mm

× 7mm QFN and

TSSOP Packages

n

General Purpose Multichannel Power Supplies:

Automotive, Industrial, Distributed Power Systems

L

, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks

of Linear Technology Corporation. All other trademarks are the property of their respective

owners.

2.25V TO 5.5V

SWA

SWB

SWE

SWF

2.25V TO 5.5V

2.7V TO 5.5V

LTC3371

C1 C2 C3

FB3

EN3

RST3

FB1

EN1

RST1

2.5V TO 5.5V

SWC

SWD

SWG

SWH

2.25V TO 5.5V

FB4

EN4

RST4

FB2

EN2

RST2

TEMP

WDI

WDO

PLL/MODE

RT

CT

GND

3371 TA01

2.2µH

2.2µH

324k

645k

412k

475k

806k

649k

665k

309k

C3

C2

C1

BUCK1 BUCK2 BUCK3 BUCK4

0

0

0

0

1

1

1

1

0

0

1

1

0

0

1

1

0

1

0

1

0

1

0

1

2A

3A

3A

4A

3A

4A

4A

4A

2A

1A

1A

1A

2A

–

–

–

2A

2A

1A

1A

–

2A

1A

–

2A

2A

3A

2A

3A

2A

3A

4A

LOAD CURRENT (mA)

1

10

100

1000 4000

0

10

20

30

40

50

60

70

80

90

100

3371 TA01b

1A BUCK

2A BUCK

3A BUCK

4A BUCK

L = 3.3µH

Burst Mode OPERATION