Battery Charger and Step-Down
Converter for Portable Applications
General Description
The AAT2556 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) product fam-
ily. It is a fully integrated 500mA battery charger
plus a 250mA step-down converter. The input volt-
age range is 4V to 6.5V for the battery charger and
2.7V to 5.5V for the step-down converter, making it
ideal for single-cell lithium-ion/polymer battery-
powered applications.
The battery charger is a complete constant current/
constant voltage linear charger. It offers an inte-
grated pass device, reverse blocking protection,
high current accuracy and voltage regulation,
charge status, and charge termination. The charg-
ing current is programmable via external resistor
from 15mA to 500mA. In addition to standard fea-
tures, the device offers over-voltage, current limit,
and thermal protection.
The step-down converter is a highly integrated
converter operating at 1.5MHz of switching fre-
quency, minimizing the size of external compo-
nents while keeping switching losses low. It has
independent input and enable pins. The output
voltage ranges from 0.6V to the input voltage. The
feedback and control deliver excellent load regula-
tion and transient response with a small output
inductor and capacitor.
The AAT2556 is available in a Pb-free, thermally-
enhanced TDFN33-12 package and is rated over
the -40°C to +85°C temperature range.
AAT2556
Features
•
SystemPower
™
•
•
•
•
Battery Charger:
— Input Voltage Range: 4V to 6.5V
— Programmable Charging Current up to
500mA
— Highly Integrated Battery Charger
— Charging Device
— Reverse Blocking Diode
Step-Down Converter:
— Input Voltage Range: 2.7V to 5.5V
— Output Voltage Range: 0.6V to V
IN
— 250mA Output Current
— Up to 96% Efficiency
— 30µA Quiescent Current
— 1.5MHz Switching Frequency
— 100µs Start-Up Time
Short-Circuit, Over-Temperature, and Current
Limit Protection
TDFN33-12 Package
-40°C to +85°C Temperature Range
Applications
•
•
•
•
•
•
Bluetooth™ Headsets
Cellular Phones
Handheld Instruments
MP3 and Portable Music Players
PDAs and Handheld Computers
Portable Media Players
Typical Application
Adapter / USB Input
ADP
VIN
EN_BUCK
STAT
BATT +
Enable
V
OUT
L= 3.3µH
LX
R
FB1
C
OUT
R
FB2
FB
GND
ISET
R
SET
EN_BAT
BAT
C
System
BATT -
Battery Pack
2556.2006.09.1.2
1
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
