PRODUCT DATASHEET
AAT1
149A
SwitchReg
TM
General Description
The AAT1149A SwitchReg is a 2.2MHz step-down con-
verter with an input voltage range of 2.2V to 5.5V. It is
optimized to react quickly to load variations and operate
with a tiny 0603 inductor that is only 1mm tall.
The AAT1149A can deliver 400mA of load current and
operates in PWM only mode for low noise operation. The
2.2MHz switching frequency minimizes the size of exter-
nal components while keeping switching losses low.
The AAT1149A is optimized for low noise portable
applications.
The AAT1149A is available in a Pb-free, space-saving
5-pin wafer-level chip scale (WLCSP) package and is
rated over the -40°C to +85°C temperature range.
2.2MHz Fast Transient 400mA Step-Down Converter
Features
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Ultra-Small 0603 Inductor (Height = 1mm)
V
IN
Range: 2.2V to 5.5V
V
OUT
Fixed 1.875V
400mA Max Output Current
Up to 98% Efficiency
3mA No Load Quiescent Current
2.2MHz Switching Frequency
70μs Soft Start
Fast Load Transient
Over-Temperature Protection
Current Limit Protection
100% Duty Cycle Low-Dropout Operation
<1μA Shutdown Current
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
AAT1149A
V
OUT
= 1.875V
L1 2.2µH
IN
C2
4.7µF
EN
AGND
PGND
LX
FB
PGND
PGND
C1
4.7µF
1149A.2008.08.1.1
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