Total Power Solution for Portable Applications
General Description
The AAT2554 is a fully integrated 500mA battery
charger, a 250mA step-down converter, and a
300mA low dropout (LDO) linear regulator. The
input voltage range is 4V to 6.5V for the battery
charger and 2.7V to 5.5V for the step-down con-
verter and linear regulator, making it ideal for
applications operating with single-cell lithium-
ion/polymer batteries.
The battery charger is a complete constant cur-
rent/constant voltage linear charger. It offers an
integrated pass device, reverse blocking protec-
tion, high accuracy current and voltage regulation,
charge status, and charge termination. The charg-
ing current is programmable via external resistor
from 15mA to 500mA. In addition to these stan-
dard features, the device offers over-voltage, cur-
rent limit, and thermal protection.
The step-down converter is a highly integrated
converter operating at a 1.5MHz 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 AAT2554 linear regulator is designed for fast
transient response and good power supply ripple
rejection. Designed for 300mA of load current,
it includes short-circuit protection and thermal
shutdown.
The AAT2554 is available in a Pb-free, thermally-
enhanced TDFN34-16 package and is rated over
the -40°C to +85°C temperature range.
AAT2554
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
Linear Regulator:
— 300mA Output Current
— Low Dropout: 400mV at 300mA
— Fast Line and Load Transient Response
— High Accuracy: ±1.5%
— 70µA Quiescent Current
Short-Circuit, Over-Temperature, and Current
Limit Protection
TDFN34-16 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
Enable
V
OUTB
R
FB1
C
OUTB
R
FB2
V
OUTA
C
OUTA
FB
OUTA
GND
ISET
L= 3.0µH
LX
ADP
STAT
EN_BAT
VINB
ENB
VINA
ENA
AAT2554
BAT
System
BATT+
C
OUT
R
SET
BATT-
Battery
Pack
2554.2007.01.1.2
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
