LTC3780

1

3780ff

For more information www.linear.com/LTC3780

Typical applicaTion

FeaTures

applicaTions

DescripTion

High Efficiency, Synchronous,

4-Switch Buck-Boost Controller

The LTC®3780 is a high performance buck-boost switch-

ing regulator controller that operates from input voltages

above, below or equal to the output voltage. The constant

frequency current mode architecture allows a phase-

lockable frequency of up to 400kHz. With a wide 4V to

30V (36V maximum) input and output range and seamless

transfers between operating modes, the LTC3780 is ideal

for automotive, telecom and battery-powered systems.

Theoperatingmodeofthecontrollerisdeterminedthrough

the FCB pin. For boost operation, the FCB mode pin can

and forced continuous mode. During buck operation, the

FCB mode pin can select among skip-cycle mode, discon-

tinuous mode and forced continuous mode. Burst Mode

operation and skip-cycle mode provide high efficiency

operation at light loads while forced continuous mode

and discontinuous mode operate at a constant frequency.

Fault protection is provided by an output overvoltage

comparatorandinternalfoldbackcurrentlimiting.Apower

good output pin indicates when the output is within 7.5%

of its designed set point.

High Efficiency Buck-Boost Converter

n

n

n

Synchronous Rectification: Up to 98% Efficiency

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Current Mode Control

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n

Phase-Lockable Fixed Frequency: 200kHz to 400kHz

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Power Good Output Voltage Monitor

n

Internal LDO for MOSFET Supply

n

Quad N-Channel MOSFET Synchronous Drive

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Adjustable Soft-Start Current Ramping

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Foldback Output Current Limiting

n

Selectable Low Current Modes

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Output Overvoltage Protection

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Available in 24-Lead SSOP and Exposed Pad

(5mm

× 5mm) 32-Lead QFN Packages

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Automotive Systems

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Telecom Systems

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DC Power Distribution Systems

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High Power Battery-Operated Devices

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Industrial Control

+

TG2

0.1µF

0.1µF

BOOST2

SW2

BG2

TG1

BOOST1

SW1

BG1

PLLIN

RUN

SS

SGND

FCB

0.010

4.7µF

A

B

D

C

2200pF

1µF

CER

100µF

16V

CER

330µF

16V

ON/OFF

0.1µF

4.7µH

20k

PGOOD

LTC3780

7.5k

1%

3780 TA01

105k

1%

22µF

50V

CER

5V TO 32V

12V

5A

+

0

90

95

100

15

25

3780 TA01b

85

80

5

10

20

30

35

75

70

8

9

10

7

6

5

4

3

2

1

0

Efficiency and Power Loss

L

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

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

respective owners. Protected by U.S. Patents, including 5481178, 6304066, 5929620, 5408150,

6580258, patent pending on current mode architecture and protection.