LTC3564_15 Datasheet, PDF (1/20 Pages) Linear Technology – 2.25MHz, 1.25A Synchronous Step-Down Regulator

FEATURES
■ _{High Efficiency: Up to 96%}
■ _{Very Low Quiescent Current: Only 20μA}
■ _{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}^TM _and
6-Lead
(2mm
×
3mm)
U
DFN
Packages
APPLICATIO S
■ _{Cellular Telephones}
■ _{Wireless and DSL Modems}
■ _{Digital Still Cameras}
■ _{Media Players}
■ _{Portable Instruments}
■ _{Point of Load Regulation}
TYPICAL APPLICATIO
1.1μH
V_IN
V_IN
SW
C_IN
22μF
CER
LTC3564
22pF
RUN V_FB
GND
634k
316k
3564 TA01a
V_OUT
1.8V
C_OUT
22μF
CER
LTC3564
2.25MHz, 1.25A
Synchronous
Step-Down Regulator
DESCRIPTIO
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
5.5V 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^® operation increases efficiency at
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.
, 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.
100
10
V_OUT = 1.8V
90
1
80
70
0.1
60
50
0.01
40
30
0.001
20
10
0
0.1
V_IN = 2.7V _0.0001
V_IN = 3.6V
V_IN = 4.2V
0.00001
1
10 100 1000 10000
OUTPUT CURRENT (mA)
3564 TA01b
3564f
1