3MHz Fast Transient
400mA Step-Down Converter
General Description
The AAT1149 SwitchReg is a 3.0MHz step-down
converter with an input voltage range of 2.7V to
5.5V and output voltage as low as 1.0V. It is opti-
mized to react quickly to load variations and oper-
ate with a tiny 0603 inductor that is only 1mm tall.
The AAT1149 output voltage is programmable via
external feedback resistors. It can deliver 400mA of
load current while maintaining a low 45μA no load
quiescent current. The 3.0MHz switching frequen-
cy 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 and is rated over
the -40°C to +85°C temperature range.
AAT1149
Features
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SwitchReg
™
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 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
IN
C2
4.7µF
EN
AGND
PGND
LX
FB
PGND
PGND
R2
59k
R1
118k
C1
4.7µF
V
OUT
= 1.8V
L1 1.8µH
1149.2006.11.1.0
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
