PRODUCT DATASHEET
AAT3177
ChargePump
TM
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
EP
High Current, High Efficiency Charge Pump with Auto-Timer
Symbol
VIN
C1+
C1-
GND
FL
RSET
EN/SET
CT
C2-
C2+
OUT
VIN
Function
Input power supply pin. Connect Pin 1 directly to Pin 12 and then to input supply voltage. Con-
nect a 4.7μF or larger ceramic capacitor to ground.
Flying capacitor C1 positive terminal. Connect a 1μF ceramic capacitor between C1+ and C1-.
Flying capacitor C1 negative terminal.
Ground connection.
Controlled current sink. Connect the
fl
ash LED cathode to this pin.
Connect resistor here to set maximum output current.
Charge pump enable / set input control pin. When in the low state, the AAT3177 is powered down
and consumes less than 1μA. When connected to logic high level, the AAT3177 charge pump is
active. This pin should not be left
fl
oating.
Flash timeout capacitor. Connect a 0.1μF capacitor between this pin and GND for a
fl
ash timeout
of 1 second.
Flying capacitor C2 negative terminal.
Flying capacitor C2 positive terminal. Connect a 1μF ceramic capacitor between C2+ and C2-.
Charge pump output. Connect a 2.2μF or larger ceramic capacitor to ground. Connect to
fl
ash
LED anode to drive the LED.
Input power supply pin. Connect Pin 12 directly to Pin 1 and then to input supply voltage.
Exposed paddle (bottom). Connect to GND directly beneath package.
Pin Configuration
TDFN33-12
(Top View)
VIN
C1+
C1-
GND
FL
RSET
1
2
3
4
5
6
12
11
10
9
8
7
VIN
OUT
C2+
C2-
CT
EN/SET
2
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3177.2008.06.1.0
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