AAT2550
Total Power Solution for Portable Applications
Pin Descriptions
Pin #
Symbol Function
1
ENA
Enable pin for Converter A. When connected to logic low, it disables the step-down converter
and consumes less than 1µA of current. When connected to logic high, the converter operates
normally.
2
LXA
Power switching node for Converter A. Connect the inductor to this pin. Internally, it is connect-
ed to the drain of both high- and low-side MOSFETs.
3, 17
PGND
Power ground. Connect the PGND pins together as close to the IC as possible. Connect
AGND to PGND at a single point as close to the IC as possible.
Status report to the microcontroller via serial interface (open drain).
Not connected.
4
5, 7
6
DATA
N/C
ADPSET
Charge current set point. Connect a resistor from this pin to ground. Refer to Typical
Characteristics curves for resistor selection.
8
BAT
ADP
Battery charging and sensing. Connect the positive terminal of the battery to BAT.
Input for adapter charger.
9
10, 11, 22
12
AGND
ENBAT
Analog signal ground. Connect AGND to PGND at a single point as close to the IC as possible.
Enable pin for the battery charger. When connected to logic low, the battery charger is dis-
abled and consumes less than 1µA of current. When connected to logic high, the charger
operates normally.
13
14
15
16
TS
Temperature sense input. Connect to a 10kΩ NTC thermistor.
Battery charge status indicator pin to drive an LED. It is an open drain input.
Battery charge status indicator pin to drive an LED. It is an open drain input.
Timing capacitor to adjust internal watchdog timer. Sets maximum charge time for adapter
powered trickle, constant current, and constant voltage charge modes.
Power switching node for Converter B. Connect the inductor to this pin. Internally, it is connect-
ed to the drain of both high- and low-side MOSFETs.
STAT2
STAT1
CT
18
19
LXB
ENB
Enable pin for Converter B. When connected to logic low, it disables the step-down converter
and consumes less than 1µA of current. When connected to logic high, the converter operates
normally.
20
21
INB
Input voltage for Converter B.
FBB
Output voltage feedback input for Converter B. FBB senses the output voltage for regulation
control. For fixed output versions, connect FBB to the output voltage. For adjustable versions,
drive FBB from the output voltage through a resistive voltage divider. The FBB regulation
threshold is 0.6V.
23
FBA
INA
Output voltage feedback input for Converter A. FBA senses the output voltage for regulation
control. For fixed output versions, connect FBA to the output voltage. For adjustable versions,
drive FBA from the output voltage through a resistive voltage divider. The FBA regulation
threshold is 0.6V.
24
Input voltage for Converter A.
EP
Exposed paddle; connect to ground directly beneath the package.
2
2550.2006.07.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
