General Description
The AAT2847 is a highly integrated power solution for single cell Li-Ion/Polymer based liquid crystal display (LCD) display applications. It includes a four channel light emitting diode (LED) backlight driver and two integrated 200mA low dropout voltage regulators (LDOs) as additional power supplies for display and camera related chipsets.
The backlight driver in the AAT2847 is a low noise tri-mode DC/DC charge pump converter. Each of the four channels of the backlight driver is capable of delivering up to 20mA of bias currents for white LEDs. The white LED (WLED) backlight bias current matching is 1% which helps provide uniform display brightness.
AnalogicTech’s AS2Cwire™ (Advanced Simple Serial Control™) serial digital interface is used to enable, disable, and set the current for each backlight LED channel. Each LED channel has sixteen available current level settings in three separate current scales, plus four available current level settings on a low level current scale.
Each LED channel is equipped with built-in short circuit protection and auto disable functionality. A low shutdown current feature disconnects the load from the input and reduces quiescent current to less than 1μA.
The AAT2847 is available in the thermally enhanced 20-pin 3x4x0.75mm TQFN package.

• Input Supply Voltage Range: 2.7V to 5.5V
• Tri-Mode (1X/1.5X/2X) Charge Pump:
- Delivers up to 120mA of Output Current
• Integrated LCD Display Solution:
- Four-Channel WLED Backlight
• User-Programmable WLED Current Scales: 30mA, 20mA and 15mA.
- Sixteen Programmable Current Level Settings
• User Selectable Low Level Current Scale
- Four Programmable Current Level Settings
- Dual 200mA LDOs (w/Separate Enables)
• Single-Wire AS2Cwire Serial Interface for Configuration/Control
- Four Addressable Registers
- Fast, 1MHz Serial Interface
• > 90% Peak Efficiency
• LDO Output Voltages:
- AAT2847-EE: User-Programmable
- AAT2847-QG: 2.8V and 1.5V
- AAT2847-QI: 2.8V and 1.8V
• Over-Temperature Protection
• Available in 3x4x0.75mm TQFN34-20 Package
• -40°C to +85°C Temperature Range

• Camera Function Power Supplies
• Camera Phone Displays
• LCD Modules
• White LED Backlighting


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General Description
The AAT1236 is a highly integrated, high efficiency power solution for white LED and keypad backlights in mobile/portable devices. It is based on a switching boost converter which steps up the single cell lithium- ion/polymer battery voltage to drive 5 strings of series-connected white LEDs with precision current regulation. The AAT1236 is capable of driving a total
of four LEDs per channel.

 The boost converter can produce an output drive of up to 24V at 100mA. The high switching frequency (up to 2MHz) provides fast response to load transients and allows the use of small external components. A fully integrated control circuit simplifies the design and reduces total solution size.

 A two-wire I2C serial digital interface is used to individually turn each output sink on/off and adjust the LED current by group. Unlike conventional pulse width modulation (PWM) control of LED brightness, the AAT1236 drives the LEDs with constant, nonpulsating current. The interface is fully compliant to the Fast/Standard mode I2C specification, allowing a transfer rate of up to 400kHz.

 A similar device is also available with a proprietary Advanced Simple Serial Control™ (AS2Cwire™) single wire interface; please see the AAT1235 datasheet.
The AAT1236 is available in a Pb-free, thermallyenhanced 16-pin 3x4mm TDFN package and is
specified for operation over the -40°C to +85°C temperature range.

• Input Supply Voltage Range: 2.7V to 5.5V
• Maximum Boost Output Drive: Up to 24V at 100mA
• Up to 85% Efficient Operation
• Up to 2MHz Switching Frequency with Small Inductor
• User-Programmable Full-Scale LED Current, Up to 30mA
• Two-Wire, I2C Compliant Serial Interface
— Two Addressable Registers
• Independent LED Current Control by Group
— Backlight Group B1-B2, 16 Settings
— Auxiliary Group A1-A3, 16 Settings
• Independent LED ON/OFF Control
— Fast, 400kHz Serial Transfer Rate
• Non-Pulsating, High-Performance LED Current Drive for Uniform Illumination
— 10% Absolute Accuracy
— 2% Channel-to-Channel Matching
• Over-Voltage and Over-Temperature Protection
• Automatic Soft-Start Minimizes Large Inrush Current at Startup
• Available in 3x4mm TDFN34-16 Package

• Digital Still Cameras (DSCs)
• Keypad Backlight
• Large Panel Displays
• Mobile Handsets
• PDAs and Notebook PCs
• Personal Media Players
• White LED Backlight


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