A8500

• 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 (V_f = 3.2 V, I_f = 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

Description

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