Battery Charger and Step-Down
Converter for Portable Applications
Pin Descriptions
Pin #
1
2, 8, 10
3
AAT2556
Symbol
FB
GND
EN_BUCK
Function
Feedback input. This pin must be connected directly to an external resistor divider.
Nominal voltage is 0.6V.
Ground.
Enable pin for the step-down converter. When connected to logic low, the step-down
converter is disabled and it consumes less than 1µA of current. When connected to
logic high, it resumes normal operation.
Enable pin for the battery charger. When internally pulled down, the battery charger is
disabled and it consumes less than 1µA of current. When connected to logic high, it
resumes normal operation.
Charge current set point. Connect a resistor from this pin to ground. Refer to typical
curves for resistor selection.
Battery charging and sensing.
Charge status input. Open drain status input.
Input for USB/adapter charger.
Output of the step-down converter. Connect the inductor to this pin. Internally, it is
connected to the drain of both high- and low-side MOSFETs.
Input voltage for the step-down converter.
Exposed paddle (bottom): connect to ground directly beneath the package.
4
EN_BAT
5
6
7
9
11
12
EP
ISET
BAT
STAT
ADP
LX
VIN
Pin Configuration
TDFN33-12
(Top View)
FB
GND
EN_BUCK
EN_BAT
ISET
BAT
1
2
3
4
5
6
12
11
10
9
8
7
VIN
LX
GND
ADP
GND
STAT
2
2556.2006.05.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
