AIC1841/2
High Efficiency 1.5X charge Pump
For White LEDs Backlighting
FEATURES
1MHz Switching Frequency
2.7V to 5.5V Input Voltage Range
Low Shutdown Current:
≦
1µA
Regulated 20mA Full-Scale Output Current
32-Position Linear Scale with Digital Control
High Accuracy Brightness Matching
33% Less Input Current Than Doubler Charge
Pump
No Inductors Required
Build-in Soft-Start
Current Limit and Over Temperature Protection
12-Pin (AIC1841) and 16-Pin (AIC1842) QFN
Package
GENERAL DESCRIPTION
The AIC1841 and AIC1842 provide 4 and 6 LED
current source outputs with regulated constant
current for uniform intensity. The AIC1841/2 is the
low noise, constant frequency charge pump
DC/DC converter that uses 1.5X conversion to
increase efficiency in white LED applications. The
devices can be used to produce current levels up
to 20mA for each output from a 2.7V to 5.5V input.
Low external parts counts (two 1
μ
F flying
capacitors and two small bypass capacitors at V
IN
,
and OUT) make the AIC1841/2 ideal for small,
battery-powered applications.
EN/SET interface is used to enable, disable and
set the LED current for a 32 level logic scale LED
brightness control. Built-in current limiting, with
thermal
shutdown
provide
protection
to
the
APPLICATIONS
Cellular Phones
PDAs
Digital Still Cameras
Handheld Devices
White LED Backlighting
AIC1841/2 against fault conditions. Automatic soft-
start circuitry prevents excessive inrush current
during start-up. 1MHz high switching frequency is
enable to use tiny external components.
The AIC1841 is available in a 12-pin thin QFN
package, and the AIC1842 is available in a space-
saving 16-pin QFN package.
Analog Integrations Corporation
3A1, No.1 Li-Hsin Rd. I, Science Park, Hsinchu 300, Taiwan
TEL: 886-3-5772500
FAX: 886-3-5772510 www.analog.com.tw
DS-1842P-02 041707
1
AIC [ ANALOG INTERGRATIONS CORPORATION ]
