A8503: High Efficiency 6-Channel, 2 MHz, WLED/RGB Driver for Medium Displays, with Integrated 55 V Power Switch

The A8503 is a multi-output WLED/RGB LED driver for medium-size LCD backlighting. It integrates a current-mode boost converter with internal power switch and six current sinks. The boost converter can provide output voltages up to 47 V. The boost converter can drive up to 72 LEDs at 20 mA per LED with a battery voltage down to 5 V. The LED sinks are capable of sinking up to 32 mA each, and can also be paralleled together to achieve even higher LED currents. The A8503 provides protection against overvoltage, open diode, open or shorted LED string, and overtemperature. A dual level cycle-by-cycle current limit function provides soft start and protects against overloads. A soft start timeout monitor is provided to enhance protection when starting up into a fault condition.

When the MODE pin is set low, the A8503 latches on a fault, and can be re-enabled only by cycling the input voltage, VIN, or by toggling the EN pin. Connecting the MODE pin high provides auto-restart after fault events. The A8503 features EN (enable) and PWM (dimming) pins to comply with popular notebook backlight control interfaces.

Applications include:

  • Notebook and sub-notebook displays
  • LCD monitors
  • LCD panels

The device package is a 26-contact, 4 mm × 4 mm, 0.75 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte tin leadframe plating.

This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available. Date of status change: June 30, 2017

Deadline for receipt of LAST TIME BUY orders: June 30, 2017.


Astrorep Inc. (Allegro and Sanken Semiconductors, Sanken Power Supplies)
700 Veterans Memorial Hwy
Suite 310
Hauppauge, NY 11788
Phone: (631)422-2500
Fax: (631)422-2504
Web: www.astrorepinc.com
Email: donna.tweedy@astrorepinc.com

If this is not your local representative, find your local sales rep here.

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  • Active current sharing between LED strings for ±0.6% accuracy and matching
  • Drives up to 12 series × 6 parallel = 72 LEDs (Vf = 3.2 V, If = 20 mA) at 5 V
  • Each individual current sink is capable of 32 mA
  • Adjustable overvoltage protection (OVP)
  • 600 kHz to 2 MHz adjustable switching frequency
  • Open or shorted LED string protection
  • Open Schottky diode protection
  • Overtemperature, cycle-by-cycle current limit, undervoltage, and soft start time-out protections
  • Selectable latched/auto-restart protection modes
  • No audible MLCC noise during PWM dimming
  • No pull-up resistors required for LED modules that use ESD capacitors
  • Extends battery life
  • Efficiency optimized for 3-cell notebooks
  • 0.1 µA shutdown current
  • Unique architecture eliminates external voltage divider and associated battery drain
  • Rugged and small footprint solution
  • 55 V, 2 A DMOS switch in 4 mm × 4 mm package—allows IPC-2221/2 / IPC-D-275 compliant PCB layout

The device package is a 26-contact, 4 mm × 4 mm, 0.75 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation (suffix EC). It is lead (Pb) free, with 100% matte tin leadframe plating.

EC QFN/MLP with exposed pad 26 lead

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Product Image Functional Block Diagram

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
A8503GECTR-T 26-lead QFN/MLP -40°C to 105°C Yes View Data Discontinued Contact your
local sales rep
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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.

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