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Programmable LED driver supports up to 17 LED sources

MILPITAS, CA — Linear Technology Corporation's LTC3208 is an 850kHz, low-noise, high-efficiency 1x/1.5x/2x charge pump LED driver that can drive up to 17 LED current sources in a single portable device.

The LTC3208 can drive: a 1-4 LED Main display, 1-2 LED Sub display, a 1-3 LED RGB display, a 1-4 Camera LED display, and a 1-4 LED Auxiliary display. Sealed in a 5mm x 5mm, 32-lead QFN package, the LTC3208 offers digital control of each display with independent dimming and programming via a two-wire I2C serial interface.

The device's input voltage range of 2.9V to 4.5V is optimized for single cell Li-Ion battery applications. When driven at the nominal 3.6V, the driver can achieve 95% efficiency with a quiescent current draw of only 250 microamps. The LTC3208 requires only four small capacitors and one resistor.

The charge pump automatically optimizes based on VIN and LED forward voltage conditions. After powering up in 1x mode, the LTC3208 switches to 1.5x boost mode when any enabled LED current source approaches dropout. A dropout switches the part into 2x mode. Maximum currents for the Main/Sub/RGB/CAM/Aux displays are set with a single resistor. LED currents are controlled with precision internal current sources while dimming and ON/OFF control for all displays are achieved via a 2-wire I2C serial interface.

The charge pump enables 256 brightness levels on the Main and Sub displays, and 4096 color combinations for the RGB display. Internal circuitry prevents inrush current and excessive input noise during start-up and mode switching.

The LTC3208 costs $2.55 in 1,000-piece quantities. Click here for the data sheet.

Linear Technology Corporation, +1 408-432-1900, http://www.linear.com/index.jsp.

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