A8500: Flexible WLED/RGB Backlight Driver for Medium Size LCDs

Description

This device is in production, however, it has been deemed Pre-End of Life. The product is approaching end of life. Within a minimum of 6 months, the device will enter its final, Last Time Buy, order phase. Date of status change: December 5, 2018

Recommended Substitutions: Contact Allegro Sales.

The A8500 is a multi-output WLED driver for medium display backlighting. The A8500 integrates a boost converter and eight current-sinks to provide a flexible 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 A8500 can support any application requiring 4 to 96 WLEDs. The boost converter is a constant frequency current-mode converter.

Each LED channel can sink 25 mA, and channels can be paralleled for higher currents. Flexible dimming allows output channels to either run at an adjustable DC value or with externally controlled PWM duty cycles.

The A8500 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

Top Features

  • Active current sharing between LED strings for ±1.5% typical current matching and ±1.2% typical accuracy
  • Drive up to 12 series × 8 parallel = 96 LEDs (Vf = 3.2 V, If = 20 mA)
  • Flexible dimming, using alternative methods:
    • LED duty cycle control (PWM pin)
    • DC current using serial programming (EN pin)
    • DC current using external PWM signal (APWM pin)
    • An external resistor
  • Boost converter with integrated 50 V, 2 A DMOS
  • LED sinks rated for 25 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
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8500EECTR-T 26-lead QFN/MLP -40°C to 85°C Yes View Data pre-EOL Contact your
local sales rep
Check
Distributor Stock
A8500GECTR-T 26-lead QFN/MLP -40°C to 105°C -- View Data Contact your
local sales rep
Check
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.

EC QFN/MLP with exposed pad 26 lead

Packaging

The A8500 is available in a 26 pin, 4 mm × 4 mm QFN/MLP package that is only 0.75 mm nominal in height (suffix EC).