1

LTC3564

3564f

■

High Efficiency: Up to 96%

■

Very Low Quiescent Current: Only 20

■

1.25A Output Current

■

2.5V to 5.5V Input Voltage Range

■

2.25MHz Constant Frequency Operation

■

No Schottky Diode Required

■

Low Dropout Operation: 100% Duty Cycle

■

0.6V Reference Allows Low Output Voltages

■

Shutdown Mode Draws

≤1μA Supply Current

■

Current Mode Operation for Excellent Line and

Load Transient Response

■

Overtemperature Protected

■

Low Profile (1mm) ThinSOT

6-Lead (2mm

× 3mm) DFN Packages

The LTC

nous buck regulator using a constant frequency, current

mode architecture. Supply current during operation is

only 20

μA, dropping to ≤1μA in shutdown. The 2.5V to

5.5V input voltage range makes the LTC3564 ideally suited

for single Li-Ion battery-powered or 3.3V to 5V input

voltage applications. 100% duty cycle provides low drop-

out operation, extending battery life in portable systems.

Automatic Burst Mode

light loads, further extending battery runtime.

Switching frequency is internally set at 2.25MHz, allowing

the use of small surface mount inductors and capacitors.

The internal synchronous switch increases efficiency and

eliminates the need for an external Schottky diode. Low

output voltages are easily supported with the 0.6V feed-

back reference voltage. The LTC3564 is available in low

profile (1mm) ThinSOT and 6-Lead (2mm

× 3mm) DFN

packages.

■

Cellular Telephones

2.25MHz, 1.25A

Synchronous

Step-Down Regulator

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

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

Burst Mode is a registered trademark of Linear Technology Corporation.

ThinSOT is a trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 5481178, 6580258, 6304066, 6498466, 6611131.

22

μF

CER

LTC3564

RUN

1.1

μH

22pF

634k

316k

3564 TA01a

SW

GND

22

μF

CER

1.8V

OUTPUT CURRENT (mA)

0.1

40

50

60

70

80

1

10

100

1000

10000

3564 TA01b

30

20

10

0

90

100

0.0001

0.001

0.01

0.1

0.00001

1

10