I2C based LED driver IC from AnalogicTech

25th June 2008

Advanced Analogic Technologies Inc., Europe

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Datasheet

Most smart phones today require some combination of backlight LED drivers for a main display, sometimes additional LED drivers for a smaller sub-display, one or more flash LED drivers, and LDOs to power the embedded camera. By rolling all these functions in various configurations into a single IC, AnalogicTech’s AAT2860 allows designers to minimise component count, board space and cost whether they are building a high end PDA-type phone with a single large display or a traditional clamshell design with two displays.

The AAT2860 is an I2C-based Lighting Management Unit (LMU) that integrates up to seven LED drivers and three Low Dropout (LDO) linear regulators in a single IC. By offering these power functions in a variety of configurations, the IC offers designers a single compact lighting solution for a wide variety of high performance camera phones.

Optimised for single-cell Lithium-ion/polymer systems, the AAT2860 operates across a 2.7V to 5.5V input voltage range. A tri-mode charge pump drives up to seven LEDs in multiple backlight and flash configurations.

The new LMU is initially available in two basic configurations. The AAT2860-1 is configured into either seven LED drivers for a main display or four for a main display and three for a sub-display. The AAT2860-2 offers six LED drivers for a main display and one flash driver or four for a main display, two for a sub display and one flash driver. Other configurations are available upon request.

The current level for each LED is enabled, disabled and set via an I2C compatible serial interface. Backlight LEDs can be programmed across 32 discrete levels from 0.5mA to 31mA. To ensure uniform display brightness, current matching is better than 3 percent.

Flash LEDs are programmable across 16 levels up to 300mA. Current matching for the flash LEDs is better than 5 percent. To protect the flash LEDs from thermal damage, the AAT2860 also includes a programmable safety timer, which will automatically terminate the flash pulse in the event of a software failure.

The AAT2860 also features three low-noise, low-dropout (LDO) linear regulators. Each LDO can deliver up to 300mA load current with 150mV dropout. Ground pin current is 80microA. Each output is programmable via I2C from 1.5 to 3.0V.

The AAT2860 also features automatic soft start and integrated thermal protection.

Qualified across the -40 to +85 degree C temperature range, the AAT2860 is available in a Pb-free, 24-pin TQFN34 package.