LTC3217

FEATURES n Charge Pump Provides High Efficiency with Automatic Mode Switching n Multimode Operation: 1x, 1.5x, 2x n Four Low Dropout LED Outputs n Up to 600mA Total Output Current n Independent Torch and Flash ISET and Enable Pins n Low Noise Constant Frequency Operation* n PWM Brightness Control via the EN2 Pin n Low Shutdown Current: 4μA n Internal Soft-Start Limits Inrush Current During Start-Up and Mode Switching n Open/Short LED Protection n No Inductors n (3mm x 3mm) 16-Lead QFN Plastic Package APPLICATIONS n Multi-LED Camera Light Supply for Cellphones/ DSCs/PDAs L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Protected by U.S. Patents including 6411531. LTC3217 600mA Low Noise Multi-LED Camera Light Charge Pumps DESCRIPTION The LTC®3217 is a low noise charge pump DC/DC converter designed to power four high current LEDs. The LTC3217 requires only four small ceramic capacitors and two current set resistors to form a complete LED power supply and current controller. Built-in soft-start circuitry prevents excessive inrush current during start-up and mode changes. High switching frequency enables the use of small external capacitors. Independent high and low current settings are programmed by two external resistors. Shutdown mode and current output levels are selected via two logic inputs. The current through the LEDs is programmed via ISET1 and ISET2. In addition, the brightn...