Linear Technology's LTC3210 is a highly integrated, 800-kHz, low-noise, high-efficiency, 1x/1.5x/2x multimode charge pump that drives a handset's main and camera LEDs. It provides five LED current sources at up to 500 mA: a four-by-25-mA LED main display, and one high-current 400-mA camera LED. Each display is digitally controlled with independent dimming and programming through a single-wire interface.
The LTC3210's 2.9- to 4.5-V input is suited for single-cell Li-Ion applications. Efficiencies when driven from a 3.6-V cell reach 95% with a quiescent current of just 400 microamps, maximizing battery run-time. High switching frequency enables the use of small external capacitors. The device requires only four small capacitors and two current set resistors.
The charge pump features low-noise constant-frequency operation and automatically optimizes efficiency based on VIN and LED forward voltage conditions. The LTC3210 is available in a low-profile (0.75-mm) 16-lead QFN 3- by 3-mm package. Pricing starts at $1.70 each for 1000-piece quantities. For more information, www.linear.com.