A8435: High Efficiency Charge Pump White LED Driver

Description

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: October 31, 2011.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, contact Allegro Sales.

The A8435 high efficiency charge pump IC offer a simple, low-cost white LED driver solution for portable electronics display applications. Using a proprietary control scheme (1, 1.5), the A8435 can output well-matched currents for up to 4 LEDs, while maintaining the highest efficiency over most of the Li-ion battery lifetime.

The A8435 accepts an input range of 2.7 to 5.5 V and delivers up to 30 mA for each of the four regulated current sources. The A8435 can deliver a total output current of 120 mA, meeting the requirements of most Li-ion battery-powered white LED backlight applications. Outputs can also be tied together for WLED flash/torch applications.

The A8435 offers flexible options for LED current driving. The LED current can be set by any of the following methods: (a) choosing an appropriate value for RSET, (b) 2-bit parallel control with 3 levels, (c) PWM control, or (d) serial programming.

The A8435 is available in a very thin profile 0.75 mm (nominal height) 3 3 mm MLP-16 package (ES), fitting the needs of space-conscious applications.

Evaluation tool and reference design are available for this device. For more information contact:  Allegro Marketing

Top Features

  • Proprietary adaptive control scheme (1, 1.5)
  • Maximum efficiency, over 92%
  • 0.5% LED current matching
  • 1 MHz operating frequency
  • Flexible dimming control:
    • Serial 11-level dimming, down to 5%
    • PWM
    • 2-bit parallel
  • Drives up to 4 white LEDs
  • 30 mA per LED
  • Low input ripple and EMI
  • Soft-start limits inrush current
  • Short circuit protection
  • Overvoltage protection
  • Thermal shutdown protection
  • Space-saving 3 3 mm MLP-16 package
  • Very thin 0.75 mm nominal height package

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8435EES-T 16-lead QFN -40°C to 85°C -- View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A8435EESTR-T 16-lead QFN -40°C to 85°C Yes View Data Discontinued 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.

Packaging

The A8435 is available in a very thin profile 0.75 mm (nominal height) 3 3 mm MLP-16 package (ES), fitting the needs of space-conscious applications.

ES-QFN with exposed pad 16 contact