High Current, High Efficiency
Charge Pump with Auto-Timer
Pin Descriptions
Pin #
1
2
3
4
5
6
7
AAT3171
Symbol
VIN
C1+
C1-
GND
FL
RSET
EN/SET
Function
Input power supply pin. Connect Pin 1 directly to Pin 12 and then to input supply voltage.
Connect 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 flash 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 AAT3171 is
powered down and consumes less than 1µA. When connected to logic high level,
the AAT3171 charge pump is active. This pin should not be left floating.
Flash timeout capacitor. Connect a 0.1µF capacitor between this pin and GND for a flash
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
flash 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.
8
9
10
11
12
EP
CT
C2-
C2+
OUT
VIN
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
3171.2007.03.1.1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
