MIC2846A

High Efficiency 6 Channel Linear WLED

Driver with DAM™, Digital Control and Dual

DAM, Dynamic Average Matching is a trademark of Micrel, Inc.

MLF and MicroLeadFrame are registered trademark Amkor Technology Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

April 2010

M9999-041210-D

General Description

The MIC2846A is a high efficiency White LED (WLED)

driver featuring two low quiescent current LDOs. It is

designed to drive up to six LEDs and greatly extend

battery life for portable display backlighting and keypad

backlighting in mobile devices. The MIC2846A architecture

provides the highest possible efficiency by eliminating

switching losses present in traditional charge pumps or

inductive boost circuits. With a typical dropout of 40mV at

20mA, the MIC2846A allows the LEDs to be driven directly

from the battery eliminating switching noise and losses

present with the use of boost circuitry.

The MIC2846A features Dynamic Averaged Matching™

(DAM™) which is specifically designed to get the optimum

matching despite process variations. This ensures a

typical matching of ±1.5% between all six LED channels.

The LED brightness is preset by an external resistor and

can be dimmed using a single-wire digital control. The

digital interface takes commands from digital programming

pulses to change the brightness in a logarithmic scale

similar to the eye’s perception of brightness. The single-

wire digital brightness control is divided into two modes of

operation; full brightness mode or battery saving mode for

a total of 49 brightness steps.

The MIC2846A also features two independently enabled

low quiescent current LDOs. Each LDO offers ±3%

accuracy over temperature, low dropout voltage (150mV

@ 150mA), and low ground current under all load

conditions (typically 35µA). Both LDOs can be turned off to

draw virtually no current.

The MIC2846A is available in the 2.5mm x 2.5mm 14-pin

Thin MLF

range of -40

°C to +125°C

Datasheet and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

WLED Driver

• High Efficiency (no Voltage Boost losses)

• Dynamic Average Matching™ (DAM™)

• Single wire digital control

• Input voltage range: 3.0V to 5.5V

• Dropout of 40mV at 20mA

• Matching better than ±1.5% (typical)

• Current accuracy better than ±1.5% (typical)

• Maintains proper regulation regardless of how many

channels are utilized

LDOs

• Very low ground current – Typical 35µA

• Stable with 1µF ceramic output capacitor

• Dropout at 150mV at 150mA

• Thermal shutdown and current limit protection

package

Applications

• Mobile handsets

• LCD Handset backlighting

• Handset keypad backlighting

• Digital cameras

• Portable media/MP3 players

• Portable navigation devices (GPS)

• Portable applications