LTC3412A

1

3412afc

APPLICATIO S

DESCRIPTIO

FEATURES

TYPICAL APPLICATIO

■

Point-of-Load Regulation

■

Notebook Computers

■

Portable Instruments

■

Distributed Power Systems

■

High Efficiency: Up to 95%

■

3A Output Current

■

Low Quiescent Current: 64μA

■

■

2.25V to 5.5V Input Voltage Range

■

Programmable Frequency: 300KHz to 4MHz

■

±2% Output Voltage Accuracy

■

0.8V Reference Allows Low Output Voltage

■

with Adjustable Burst Clamp

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Synchronizable Switching Frequency

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Low Dropout Operation: 100% Duty Cycle

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Power Good Output Voltage Monitor

■

Overtemperature Protected

■

Available in 16-Lead Exposed Pad TSSOP and

QFN Packages

3A, 4MHz, Monolithic

Synchronous Step-Down Regulator

nous, step-down DC/DC converter utilizing a constant

frequency, current mode architecture. It operates from

an input voltage range of 2.25V to 5.5V and provides a

regulated output voltage from 0.8V to 5V while deliver-

ing up to 3A of output current. The internal synchronous

power switch with 77mΩ on-resistance increases efficiency

and eliminates the need for an external Schottky diode.

Switching frequency is set by an external resistor or can

be synchronized to an external clock. 100% duty cycle

provides low dropout operation extending battery life in

transient response to be optimized over a wide range of

loads and output capacitors.

The LTC3412A can be configured for either Burst Mode

operation or forced continuous operation. Forced continu-

ous operation reduces noise and RF interference while

Burst Mode operation provides high efficiency by reducing

gate charge losses at light loads. In Burst Mode operation,

external control of the burst clamp level allows the output

voltage ripple to be adjusted according to the application

requirements.

3412A F01a

SYNC/MODE

PGOOD

SW

PGND

SGND

RT

RUN/SS

LTC3412A

294k

22μF

100μF

×2

0.47μH

2.5V AT 3A

3.3V

1000pF

2.2M

820pF

12.1k

115k

69.8k

392k

Efficiency and Power Loss

Figure 1. 2.5V/3A Step-Down Regulator

LOAD CURRENT (A)

0.01

100

95

90

85

80

75

70

65

60

55

50

100000

10000

1000

100

10

1

0.1

1

10

3412A F01b

EFFICIENCY

POWER LOSS

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

Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466,

6611131, 6724174.