LTC3215

Features:

High Efficiency Operation: 1x, 1.5x or 2x Boost Modes with Automatic Mode Switching
Ultralow Dropout ILED Current Control
Output Current up to 700mA
Low Noise Constant Frequency Operation*
Wide VIN 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


Application

LED Torch/Camera Light Supply for Cell Phones,PDAs and Digital Cameras
General Lighting and/or Flash/Strobe Applications


Specifications

VIN to GND ............................................... 0.3V to 5.5V
CPO to GND ............................................. 0.3V to 5.5V
EN ................................................... 0.3V to VIN + 0.3V
ICPO, IILED (Note 2) ........................................... 1000mA
CPO Short-Circuit Duration ............................ Indefinite
Storage Temperature Range ................. 65°C to 125°C
Operating Temperature Range (Note 3) .. 40°C to 85°C

Description

The LTC®3215 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, batterypowered
applications.

Built-in soft-start circuitry of LTC3215 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 VIN during shutdown.

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