LTC3406-1.5_15 Datasheet, PDF (1/16 Pages) Linear Technology – 1.5MHz, 600mA Synchronous Step-Down Regulator in ThinSOT

FEATURES
■ _{High Efficiency: Up to 96%}
■ _{Very Low Quiescent Current: Only 20µA}
During Operation
■ _{600mA Output Current}
■ _{2.5V to 5.5V Input Voltage Range}
■ _{1.5MHz 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 _Package
U
APPLICATIO S
■ _{Cellular Telephones}
■ _{Personal Information Appliances}
■ _{Wireless and DSL Modems}
■ _{Digital Still Cameras}
■ _{MP3 Players}
■ _{Portable Instruments}
LTC3406
LTC3406-1.5/LTC3406-1.8
1.5MHz, 600mA
Synchronous Step-Down
Regulator in ThinSOT
DESCRIPTIO
The LTC^®3406 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. The device is available in an adjustable
version and fixed output voltages of 1.5V and 1.8V. Supply
current during operation is only 20µA and drops to ≤1µA
in shutdown. The 2.5V to 5.5V input voltage range makes
the LTC3406 ideally suited for single Li-Ion battery-pow-
ered applications. 100% duty cycle provides low dropout
operation, extending battery life in portable systems.
Automatic Burst Mode^® operation increases efficiency at
light loads, further extending battery life.
Switching frequency is internally set at 1.5MHz, 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 LTC3406 is available in a low
profile (1mm) ThinSOT package.
, LTC and LT 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.
Protected by U.S. Patents, including 6580258, 5481178.
TYPICAL APPLICATIO
V_IN
2.7V
TO 5.5V
C_IN**
4.7µF
CER
4
V_IN
3 ^2.2µH*
SW
LTC3406-1.8
1
5
RUN V_OUT
GND
2
C_OUT^†
10µF
CER
V_OUT
1.8V
600mA
3406 F01a
*MURATA LQH32CN2R2M33
**TAIYO YUDEN JMK212BJ475MG
†_{TAIYO YUDEN JMK316BJ106ML}
Figure 1a. High Efficiency Step-Down Converter
95
V_IN = 2.7V
90
85
V_IN = 3.6V
80
V_IN = 4.2V
75
70
65
60
0.1
V_OUT = 1.8V
1
10
100
OUTPUT CURRENT (mA)
1000
3406 F01b
Figure 1b. Efficiency vs Load Current
3406fa
1