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LT1339

High Power Synchronous

DC/DC Controller

FEATURES

The LT

switching regulator controller. The IC drives dual

N-channel MOSFETs to create a single IC solution for high

power DC/DC converters in applications up to 60V.

The LT1339 incorporates programmable average current

limiting, allowing accurate limiting of DC load current

independent of inductor ripple current. The IC also incor-

porates user-adjustable slope compensation for minimi-

zation of magnetics at duty cycles up to 90%.

The LT1339 timing oscillator operating frequency is pro-

grammable and can be synchronized up to 150kHz. Mini-

mum off-time operation provides main switch protection.

The IC also incorporates a soft start feature that is gated by

both shutdown and undervoltage lockout conditions.

An output phase reversal pin allows flexibility in configu-

ration of converter types, including inverting and negative

topologies.

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High Voltage: Operation Up to 60V

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High Current: Dual N-Channel Synchronous Drive

Handles Up to 10,000pF Gate Capacitance

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Programmable Average Load Current Limiting

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5V Reference Output with 10mA External

Loading Capability

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Programmable Fixed Frequency Synchronizable

Current Mode Operation Up to 150kHz

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Undervoltage Lockout with Hysteresis

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Programmable Start Inhibit for Power Supply

Sequencing and Protection

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Adaptive Nonoverlapping Gate Drive Prevents

Shoot-Through

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48V Telecom Power Supplies

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Personal Computers and Peripherals

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Distributed Power Converters

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Industrial Control Systems

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Lead-Acid Battery Backup Systems

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Automotive and Heavy Equipment

, LTC and LT are registered trademarks of Linear Technology Corporation.

28V to 5V 20A Buck Converter

SYNC

TG

CT

TS

SL/ADJ

BG

SS

PGND

PHASE

SGND

RUN/SHDN

DBST

IN5819

12V

28V

1500

µF

63V

× 3

IRL3803

IRL3103D2

× 2

L1

10

µH

5V AT 20A

1k

3k

LT1339

+

CBST

1

µF

+

47

µF

+

2200

µF

6.3V

× 2

+

D2

MBR0520

D1

MBR0520

100k

0.005

Ω

10k

2200pF

2200pF

0.1

µF

1339 TA03

L1 = CTX02-13400-X2

1

µF

+

+

28V to 5V Efficiency

OUTPUT CURRENT (A)

0

20

1339 TA03a

5

10

15

100

90

80

70

60

50