AIC1841

Features:

1MHz Switching Frequency
2.7V to 5.5V Input Voltage Range
Low Shutdown Current: 1mA
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

Application

Cellular Phones
PDAs
Digital Still Cameras
Handheld Devices
White LED Backlighting




Pinout

Description

The AIC1841/2 provides 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 1gF flying capacitors and two small bypass capacitors at VIN, 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 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.