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LED driver powers nine LEDs for cell phone displays

Milpitas, Calif. — Linear Technology Corp. has released the high-efficiency and low noise LTC3219 LED driver for cell phone displays. The inductorless (charge pump) IC provides nine individually configurable current sources for main, sub and RGB displays.

The LTC3219 offers a 2.9-V to 5.5-V input voltage range, which is optimized for single cell Li-ion/polymer battery applications. Efficiencies when driven from a lithium battery (3.6 V nominal) reach 91% with a quiescent current of only 400 uA, maximizing battery run-time. Slew-rate limited switching reduces conducted and radiated noise (EMI), said Linear.

Display currents are set via a precision internal current reference. The universal current sources can be digitally controlled with independent dimming, brightness, blinking, and gradation control, and is programmable via a two-wire I2C serial interface.

The LTC3219 driver's multimode 1x/1.5x/2x charge pump features low-noise constant-frequency operation, automatically optimizing efficiency based on the voltages across the LED current sources. The device powers up in 1x mode and automatically switches to boost mode (1.5x) when any enabled LED current source approaches dropout; a subsequent dropout switches the device into doubler (2x) mode. Internal circuitry prevents inrush current and excessive input noise during start-up and mode switching. The device also provides short circuit and thermal protection.

The LTC3219 is housed in a low-profile (0.75 mm) 20-lead QFN (3 x 3mm) package. The IC requires only five small capacitors for a tiny, complete LED power supply and current controller solution, said Linear.

Pricing: Pricing starts at $1.80 each in quantities of 1,000.
Availability: From stock
Product information: LTC3219

Linear Technology Corp. , 1-408-432-1900, www.linear.com

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