LTC3564
2.25MHz, 1.25A
Synchronous
Step-Down Regulator
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DESCRIPTIO
FEATURES
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High Efficiency: Up to 96%
The LTC®3564 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. Supply current during operation is
only 20μA, dropping to ≤1μA in shutdown. The 2.5V to
5.5VinputvoltagerangemakestheLTC3564ideallysuited
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® operation increases efficiency at
light loads, further extending battery runtime.
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Very Low Quiescent Current: Only 20μA
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1.25A Output Current
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2.5V to 5.5V Input Voltage Range
2.25MHz Constant Frequency Operation
No Schottky Diode Required
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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
Switching frequency is internally set at 2.25MHz, allowing
the use of small surface mount inductors and capacitors.
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Overtemperature Protected
Low Profile (1mm) ThinSOTTM and
6-Lead (2mm × 3mm) DFN Packages
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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.
, 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.
APPLICATIO S
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Cellular Telephones
Wireless and DSL Modems
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Digital Still Cameras
Media Players
Portable Instruments
Point of Load Regulation
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TYPICAL APPLICATIO
100
90
10
V
= 1.8V
OUT
1
80
70
0.1
60
50
1.1μH
22pF
V
OUT
1.8V
0.01
0.001
0.0001
0.00001
V
IN
V
SW
LTC3564
IN
C
IN
40
30
20
10
0
C
22μF
OUT
22μF
CER
CER
RUN
GND
V
FB
V
V
V
= 2.7V
= 3.6V
= 4.2V
IN
IN
IN
634k
316k
0.1
1
10
100
1000
10000
3564 TA01a
OUTPUT CURRENT (mA)
3564 TA01b
3564f
1