Description

The YB1518 is a step-up DC-DC converter; operates as current source to drive up to 6 white LEDs(VIN at 3.0V) or 8 LEDs(VIN at 3.5V) or 9 LEDs(VIN at 3.5V) in series. Series connecting of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The light intensity of these LEDs is proportional to the current passing through them. The YB1518 switches at a fixed frequency of ~930KHz, allowing the use of tiny, low profile inductors and capacitors to minimize footprint and cost in space consideration applications for cellular phone backlighting or other hand

held equipment.

Features

■ Built-in internal switch

■ 2.7V to 7V input range

■ <1uA shutdown current

■ PWM dimming control 100Hz to 1KHz

■ Analog dimming control

■ Internal Soft Start

■ Drives up to 9 white LEDs(VIN at 3.5V)

■ Over voltage protection 34V

■ Small 5-Lead SOT-23 package

■ 100mV Low Reference Voltage

Applications

■ LCD Display Module

■ White LED Backlighting

■ PDAs, GPS terminals

■ Digital Cameras

■ Cellular Phone

■ Electronic Books

■ Portable Applications