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Related Links:

Datasheets:
A8504: WLED/RGB Backlight Driver for Medium Size LCDs (PDF)

Selection Guides:
Power Management ICs,

Power Management ICs: Display Power and Backlight

when this product is updated

A8504
WLED/RGB Backlight Driver for Medium Size LCDs

Features

• Active current sharing among 8 LED strings for ±1.3% typical current matching
• ±1.2% typical current accuracy
• Drive up to 11 series × 8 parallel = 88 LEDs (Vf = 3.5 V, If = 40 mA)
• External PWM control for LED dimming
• An external resistor for LED current setting
• Boost converter with integrated 50 V, 2 A DMOS
• LED sinks rated for 45 mA
• 200 kHz to 2 MHz switching frequency
• Open LED disconnect
• Boost current limit, thermal shutdown, and soft start
• No audible ceramic capacitor noise during PWM dimming
• Adjustable overvoltage protection (OVP)
• No pull-up resistors required for LED modules that use ESD capacitors

Description

The A8504 is a multi-output WLED driver for medium display backlighting. The A8504 integrates a boost converter and eight current-sinks to provide a WLED/RGB backlight driver. The boost converter can provide output voltage up to 47 V. The flexible channel selection control and high voltage capability allow a wide range of LED backlight applications. The boost converter is a constant frequency current-mode converter. Each LED channel can sink 45 mA, and channels can be paralleled for higher currents. LED current can be controlled with external PWM duty cycle.

The A8504 is available in a 26 pin, 4 mm × 4 mm QFN/MLP package that is only 0.75 mm nominal in height. Applications include:

• Thin notebook displays
• LCD TV
• RGB backlight
• GPS systems
• Portable DVD players

Functional Block Diagram

Complete Part Numbers

Part Number	Package Type	RoHS Compliant	Part Composition/ RoHS Data	Temperature	Comments	Samples	Distributor Stock
A8504EECTR-T	26-lead QFN/MLP	Yes	view data	-40 °C to  85 °C	new	Due to warehouse relocation, samples will be unavailable until July 21, 2008. Contact your sales rep or purchase from distributor.

Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.