LTC3419

1

3419f

OUTPUT CURRENT (mA)

100

90

80

70

60

50

40

30

20

10

0

10

1

0.1

0.01

0.001

0.0001

0.1

10

100

1000

3419 TA01b

1

■

Cellular Telephones

■

Digital Still Cameras

■

Wireless and DSL Modems

■

Portable Media Players

■

PDAs/Palmtop PCs

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Dual Monolithic 600mA

Synchronous Step-Down

Regulator

synchronous step-down DC/DC converter in a tiny

3mm × 3mm DFN package. 100% duty cycle provides

low dropout operation, extending battery life in portable

systems. Low output voltages are supported with the 0.6V

feedback reference voltage. Each regulator can supply

600mA output current.

The input voltage range is 2.5V to 5.5V, making it ideal

for Li-Ion and USB powered applications. Supply cur-

rent during operation is only 35μA and drops to <1μA in

shutdown. A user-selectable mode input allows the user

to trade off between high efficiency Burst Mode operation

and pulse-skipping mode.

An internally set 2.25MHz switching frequency allows the

use of tiny surface mount inductors and capacitors. Inter-

nal soft-start reduces inrush current during start-up. Both

outputs are internally compensated to work with ceramic

output capacitors. The LTC3419 is available in a low profile

(0.75mm) 3mm × 3mm DFN package. The LTC3419 is also

available in a fixed output voltage configuration selected

via internal resistor dividers (see Table 2).

Dual Monolithic Buck Regulator in 8-Lead 3 × 3 DFN

■

High Efficiency Dual Step-Down Outputs: Up to 96%

■

■

Only 35μA Quiescent Current During Operation

(Both Channels)

■

2.25MHz Constant-Frequency Operation

■

2.5V to 5.5V Input Voltage Range

■

Low Dropout Operation: 100% Duty Cycle

■

No Schottky Diodes Required

■

Internally Compensated for All Ceramic Capacitors

■

Independent Internal Soft-Start for Each Channel

■

Available in Fixed Output Versions

■

Current Mode Operation for Excellent Line and Load

Transient Response

■

0.6V Reference Allows Low Output Voltages

■

■

Short-Circuit Protected

■

■

Available in Small MSOP or 3mm × 3mm

DFN-8 Packages

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

Burst Mode is a registered trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners. Protected by U.S. Patents,

including 5481178, 6127815, 6304066, 6498466, 6580258, 6611131.

Efficiency and Power Loss vs

Output Current

RUN2

RUN1

LTC3419

SW2

SW1

MODE

22pF

22pF

GND

2.5V TO 5.5V

1.8V AT

600mA

2.5V AT

600mA

3419 TA01

118k

187k

59k

59k

3.3

μH3.3μH

10

μF

10

μF

10

μF