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Rev. C – 10/31/2007

SP6887 4 Channel WLED Driver

© 2007 Exar Corporation

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FEATURES

Peak Efficiency: 90%

Individual Current Regulation

3-bit Digital Output Control

1x and 1.5x Modes of Operation

Current Matching with a Max Tolerance of 3%

Output Current up to 30mA per LED

Fixed Frequency of 1MHz

Open LED Protection

Pb-Free Thin QFN-16 3mmx3mm Package

APPLICATIONS

Cellular Phones

LED backlighting

LCD Modules

Handheld Devices

Digital Cameras

PDAs

MP3 Players

DESCRIPTION

The SP6887 is a 4-channel charge pump white LED driver, capable of driving up to 4 LEDs

connected in parallel. The device operates in either 1x mode or 1.5x fractional mode, and it

can switch from 1x mode to 1.5x mode automatically when the input voltage decreases. Its

internal 4 current sink regulators ensure both LED current matching and brightness

between the RSET pin and ground. LED currents of up to 30mA are supported by the input

supply voltage over a range of 2.7V to 5.5V, making the device optimized for Li-Ion battery

applications. The SP6887 has a fixed switching frequency of 1MHz, allowing the use of very

small value ceramic capacitors. The enable input pin allows the device to be placed in

shutdown mode while reducing current consumption to less than 1µA. LED dimming can be

done by several methods including using a DC voltage to set the RSET pin current, adding a

switched resistor in parallel with RSET or applying a PWM signal to CTRx pin or EN pin.

TYPICAL APPLICATION CIRCUIT