Features

• High Efficiency Operation: 1x, 1.5x or 2x Boost Modes with Automatic Mode Switching
• Ultralow Dropout I_LED Current Control
• Output Current up to 700mA
• Low Noise Constant Frequency Operation*
• Wide V_IN Range: 2.9V to 4.4V
• Open/Shorted LED Protection
• LED Disconnect in Shutdown
• Low Shutdown Current: 2.5µA
• 4% LED Current Programming Accuracy
• Automatic Soft-Start Limits Inrush Current
• No Inductors
• Tiny Application Circuit (All Components <1mm Profile)
• 3mm × 3mm 10-Lead DFN Package

Typical Application

Description

The LTC3215 is a low noise, high current charge pump DC/DC converter designed to power high current LEDs. The part includes an accurate programmable current source capable of driving loads up to 700mA from a 2.9V to 4.4V input. Low external parts count (two flying capacitors, one programming resistor and two bypass capacitors) makes the LTC3215 ideally suited for small, battery powered applications.

Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. LED current is programmed with an external resistor. The LED is disconnected from V_IN during shutdown.

An ultralow dropout current source maintains accurate LED current at very low I_LED voltages. Automatic mode switching optimizes efficiency by monitoring the voltage across the LED current source and switching modes only when I_LED dropout is detected. The LTC3215 is available in a low profile 3mm × 3mm 10-Lead DFN package.