PRODUCT DATASHEET
AAT1
149
SwitchReg
TM
General Description
The AAT1149 SwitchReg is a 3.0MHz step-down con-
verter with an input voltage range of 2.7V to 5.5V and
output voltage as low as 1.0V. It is optimized to react
quickly to load variations and operate with a tiny 0603
inductor that is only 1mm tall.
The AAT1149 output voltage is programmable via exter-
nal feedback resistors. It can deliver 400mA of load cur-
rent while maintaining a low 45μA no load quiescent
current. The 3.0MHz switching frequency minimizes the
size of external components while keeping switching
losses low.
The AAT1149 maintains high efficiency throughout
the operating range, which is critical for portable
applications.
The AAT1149 is available in a Pb-free, space-saving
2.0x2.1mm SC70JW-8 package or a 5-pin wafer-level
chip scale (WLCSP) package and is rated over the -40°C
to +85°C temperature range.
3MHz Fast Transient 400mA Step-Down Converter
Features
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Ultra-Small 0603 Inductor (Height = 1mm)
V
IN
Range: 2.7V to 5.5V
V
OUT
Adjustable from 1.0V to V
IN
400mA Max Output Current
Up to 98% Efficiency
45μA No Load Quiescent Current
3.0MHz Switching Frequency
70μs Soft Start
Fast Load Transient
Over-Temperature Protection
Current Limit Protection
100% Duty Cycle Low-Dropout Operation
<1μA Shutdown Current
SC70JW-8 or 0.9x1.2mm WLCSP Package
Temperature Range: -40°C to +85°C
Applications
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Cellular Phones
Digital Cameras
Handheld Instruments
Microprocessor / DSP Core / IO Power
PDAs and Handheld Computers
USB Devices
Typical Application
V
IN
= 3.6V
U1
AAT1149
V
OUT
= 1.8V
L1 1.8µH
LX
FB
PGND
PGND
R2
59k
R1
118k
C1
4.7µF
IN
C2
4.7µF
EN
AGND
PGND
1149.2008.08.1.3
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