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High-Performance Power and Hall-Effect Sensor ICs

A8430
White LED Driver - Constant Current Step-Up Converter

Pin-Out or Package

DISCONTINUED PRODUCT: These parts are no longer in production The device should not be purchased for new design applications. Samples are no longer available.

Date of status change: May 3, 2010.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to your Allegro sales representative.

Features

  • Output voltage up to 36 V
  • 2.5 V to 10 V input
  • Drives up to 4 LEDs at 20 mA from a 2.5 V supply
  • Drives up to 5 LEDs at 20 mA from a 3 V supply
  • 1.2 MHz switching frequency
  • 300 mA switch current limit
  • 1 µA shutdown current

Applications

  • LED backlights
  • Portable battery-powered equipment
  • Cellular phones
  • PDAs (Personal Digital Assistant)
  • Camcorders, personal stereos, MP3 players, cameras
  • Mobile GPS systems

Description

The A8430 is a noninverting boost converter that steps-up the input voltage, to provide a programmable constant current output at up to 36 V for driving white LEDs in series. Driving LEDs in series ensures identical currents and uniform brightness. Up to four white LEDs can be driven at 20 mA from a single cell Li-ion or a multicell NiMH power source. Up to seven white LEDs can be driven by increasing the supply voltage up to 10 V.

The A8430 incorporates a power switch and feedback sense amplifier to provide a solution with minimum external components. The output current can be set by adjusting a single external sense resistor and can be varied with a voltage or filtered PWM signal when dimming control is required. The high switching frequency of 1.2 MHz allows the use of small inductor and capacitor values.

The A8430 is provided in a 5-pin 3 mm x 3 mm MLP package (part number suffix EK), that has a nominal height of only 0.75 mm. The lead-free version (part number suffix EK-T) has 100% lead-free matte tin leadframe plating.

Functional Block Diagram

Functional Block Diagram

Complete Part Numbers
Part Number Package Type RoHS
Compliant
Part Composition/
RoHS Data
Temperature Comments Samples Distributor Stock
A8431EEH-T 6-lead MLP Yes view data -40 °C to  85 °C discontinued   Contact Local Sales Representative
or check distributor stock
 
A8431EEHTR-T 6-lead MLP Yes view data -40 °C to  85 °C discontinued   Contact Local Sales Representative
or check distributor stock

Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.

Copyright © 2010 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Worcester, MA 01606 USA Phone: 1.508.853.5000 Fax: 1.508.853.7895