DESCRIPTION

· The LT3909 is a 2-string × 60mA LED driver with a fixed 2MHz step-up DC/DC converter, capable of driving up to 36V of LEDs.

· Each LED string features an accurate high-side current source with ±2% current matching.

· Output voltage adapts to LED VF variations for optimum efficiency.

· LED current is programmable from 10mA to 60mA per string using a single resistor.

· Supports analog dimming (up to 10:1) and PWM dimming (up to 40,000:1 at 100Hz, up to 160:1 at 25kHz).

· Includes programmable maximum VOUT for open LED protection, fault flag for open-LED or LED-short-to-GND, and internal thermal regulation.

FEATURES

· Wide input range: 2.9V to 40V.

· Integrated Schottky diode and internal 400mΩ, 40V, 1A switch.

· Single resistor sets LED current for both high-side current sources.

· LED current regulated even for VIN > VOUT.

· Internal compensation, soft-start, and thermal regulation.

· Accurate EN/UVLO threshold and fixed 2MHz switching frequency.

APPLICATIONS

· PDAs and handheld computers.

· GPS receivers.

· Automotive displays.

· High contrast instrument clusters.