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ADM8843:  Four White LED Backlight Driver

Product Details


The ADM8843 uses charge pump technology to provide the power to drive up to four LEDs. The LEDs are used for back-lighting a color LCD display that has regulated constant current for uniform brightness intensity. The main display can use up to three LEDs, and the sub display uses one LED. The CTRL1 and CTRL2 digital input control pins control the shutdown opera-tion and the brightness of the main and sub displays.

To maximize power efficiency, the charge pump can operate in 1×, 1.5×, or 2× mode. The charge pump automatically switches among 1×/1.5×/2× modes, based on the input voltage, to maintain sufficient drive for the LED anodes at the highest power efficiency.

Improved brightness matching of the LEDs is achieved by a feedback pin that senses individual LED current with a typical matching accuracy of 0.3%.

Applications

  • Cellular phones with main and sub displays
  • White LED backlighting
  • Camera flash/strobes and movie light applications
  • Micro TFT color displays
  • DSC
  • PDAs

FEATURES and BENEFITS

  • Drives 4 LEDs from a 2.6 V to 5.5 V (Li-Ion) input supply
  • 1×/1.5×/2× fractional charge pump to maximize power efficiency
  • 0.3% typical LED current matching
  • Up to 88% power efficiency over Li-Ion range
  • Powers main and sub display LEDs with individual shutdown
  • Package footprint only 9 mm2 (3 mm × 3 mm)
  • Package height only 0.55 mm
  • Low power shutdown mode
  • Shutdown function
  • Soft start limiting in-rush current

Functional Block Diagram for ADM8843

Documentation

Title Content Type File Type
ADM8843: Four White LED Backlight Driver Data Sheet (Rev C, 01/2011) (pdf, 372 kB) Data Sheets PDF
Isolating Power in Communication Bus and Gate Drive Applications
Starting with a communications application overview of small power options through the process of selecting the right power products this webcast is a great resource for your communications applications designs.
Webcasts WEBCAST
Innovative Power Reduction Techniques Enable Handset Manufacturers to Provide Media Rich Devices
The demand for mobile devices with high-end features has been rapidly increasing. Features like text messaging, gaming, GPS navigation, web browsing and video playback on high resolution color displays are becoming the norm in today’s portable consumer electronics market.
(LED Journal, August/September 2009)
Technical Articles HTML
Charge Pump Application Bulletin  (pdf, 970 kB)
All new applications guide for charge pumps
Overview PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

ADM8843 Evaluation Tools
Model Description Price RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
ADM8843EB-EVALZ Status: Production Evaluation Board $156.35 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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