SP6887 Datasheet, PDF (1/10 Pages) Exar Corporation – 4 CHANNEL REGULATED CHARGE PUMP WLED DRIVER

SP6887
4 CHANNEL REGULATED CHARGE PUMP WLED DRIVER
FEATURES
ƒ Peak Efficiency: 90%
ƒ Individual Current Regulation
ƒ 3-bit Digital Output Control
ƒ 1x and 1.5x Modes of Operation
ƒ Current Matching with a Max Tolerance of 3%
ƒ Output Current up to 30mA per LED
ƒ Fixed Frequency of 1MHz
ƒ Open LED Protection
ƒ Pb-Free Thin QFN-16 3mmx3mm Package
APPLICATIONS
ƒ Cellular Phones
ƒ LED backlighting
ƒ LCD Modules
ƒ Handheld Devices
ƒ Digital Cameras
ƒ PDAs
ƒ 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
uniformity. The LED current can be programmed by an external resistor, R_SET, connected
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
Rev. C – 10/31/2007
SP6887 4 Channel WLED Driver
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© 2007 Exar Corporation