A8504: WLED/RGB Backlight Driver for Medium Size LCDs


These parts are discontinued.  Samples are no longer available. For new customers or new applications, please contact Allegro. Date of status change: December 2, 2013.

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.

Applications include:

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

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

Top 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

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
A8504EECTR-T 26-lead QFN/MLP -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.


The A8504 is available in a 26 pin, 4 mm × 4 mm QFN/MLP package that is only 0.75 mm nominal in height (suffix EC).

EC QFN/MLP with exposed pad 26 lead