PRODUCT DATASHEET
AAT1145
SwitchReg
TM
General Description
The AAT1145 SwitchReg™ is a 1.2MHz constant fre-
quency current mode PWM step-down converter. It is
ideal for portable equipment requiring very high current
up to 1.5A from single-cell Lithium-ion batteries while
still achieving over 90% efficiency during peak load con-
ditions. The AAT1145 also can run at 100% duty cycle
for low dropout operation, extending battery life in por-
table systems while light load operation provides very
low output ripple for noise sensitive applications.
The AAT1145 can supply up to 1.5A output load current
from a 2.5V to 5.5V input voltage and the output voltage
can be regulated as low as 0.6V. The high switching fre-
quency minimizes the size of external components while
keeping switching losses low. The internal slope compen-
sation setting allows the device to operate with smaller
inductor values to optimize size and provide efficient
operation.
The AAT1145 is available in adjustable (0.6V to V
IN
) and
fixed (1.8V) output voltage versions. The device is avail-
able in a Pb-free, 3x3mm 10-lead TDFN package and is
rated over the -40°C to +85°C temperature range.
1.5A Step-Down Converter
Features
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Input Voltage Range: 2.5V to 5.5V
Output Voltages from 0.6V to V
IN
1.5A Output Current
High Efficiency: Up to 95%
1.2MHz Constant Switching Frequency
Low R
DS(ON)
Internal Switches: 135mΩ, 95mΩ
Allows Use of Ceramic Capacitors
Current Mode Operation for Excellent Line and Load
Transient Response
Short-Circuit and Thermal Fault Protection
Soft Start
Low Dropout Operation: 100% Duty Cycle
Low Shutdown Current: I
SHUTDOWN
< 1μA
TDFN33-10 Package
-40°C to +85°C Temperature Range
Applications
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Cellular Phones
Digital Cameras
DSP Core Supplies
PDAs
Portable Instruments
Smart Phones
Typical Application
L1
2.2μH
1
2
3
VIN 2.5V-5.5V
VOUT
1.8V,1.5A
EN
IN
AIN
LX
LX
8
7
5
10
9
C1
10μF
AAT1145-1.8
OUT
PGND
PGND
C2
22μF
6
4
AGND
AGND
1145.2008.01.1.2
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