PRODUCT DATASHEET
AAT2550178
SystemPower
TM
General Description
Total Power Solution for Portable Applications
Features
• Two Step-Down Converters:
▪
600mA Output Current per Converter
▪
V
IN
Range: 2.7V to 5.5V
▪
1.4MHz Switching Frequency
▪
Low R
DS(ON)
0.4Ω Integrated Power Switches
▪
Internal Soft Start
▪
27μA Quiescent Current per Converter
• Highly Integrated Battery Charger:
▪
Programmable Charging Current from 100mA to 1A
▪
Pass Device
▪
Reverse Blocking Diodes
▪
Current Sensing Resistor
▪
Digital Thermal Regulation
• Short-Circuit, Over-Temperature, and Current Limit
Protection
• QFN44-24 Package
• -40°C to +85°C Temperature Range
The AAT2550 is a fully integrated total power solution
with two step-down converters plus a single-cell lithium-
ion / polymer battery charger. The step-down converter
input voltage range spans 2.7V to 5.5V, making the
AAT2550 ideal for systems powered by single-cell lithi-
um-ion/polymer batteries.
The battery charger is a complete constant current/ con-
stant voltage linear charger. It offers an integrated pass
device, reverse blocking protection, high current accu-
racy and voltage regulation, charge status, and charge
termination. The charging current is programmable via
external resistor from 100mA to 1A. In addition to these
standard features, the device offers over-voltage, over-
current, and thermal protection.
The two step-down converters are highly integrated,
operating at a switching frequency of 1.4MHz, minimiz-
ing the size of external components while keeping
switching losses low. Each converter has independent
input, enable, and feedback pins. The output voltage
ranges from 0.6V to V
IN
. Each converter is capable of
delivering up to 600mA of load current.
The AAT2550 is available in a Pb-free, space-saving,
thermally-enhanced QFN44-24 package and is rated
over the -40°C to +85°C temperature range.
Applications
•
•
•
•
•
Cellular Telephones
Digital Cameras
Handheld Instruments
MP3, Portable Music, and Portable Media Players
PDAs and Handheld Computers
Typical Application
Battery Pack
Adapter
ADP
BAT
Batt+
AAT2550
STAT1
STAT2
Serial Interface
R
SET
TS
Batt-
DATA
ADPSET
CT
Temp
LXA
ENBAT
INA
Li-Ion Battery or
Adapter
V
OUTA
C
OUTA
FBA
LXB
FBB
GND
V
OUTB
C
OUTB
INB
ENA
ENB
2550.2008.02.1.3
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