1FEATURES

2• Synchronous Rectification, High Efficiency

and no External Schottky Diode required

• Uses Small Surface Mount Components

• Can Drive 2-5 White LEDs in Series (May

Function with More Low VF LEDs)

• 2.7V to 7V Input Range

• True Shutdown Isolation, no LED Leakage

Current

• DC Voltage LED Current Control

• Input Undervoltage Lockout

• Internal Output Over-Voltage Protection (OVP)

Circuitry, with no External Zener Diode

Required LM3501-16: 15.5V OVP; LM3501-21:

20.5V OVP.

• Requires Only a Small 16V (LM3501-16) or 25V

(LM3501-21) Ceramic Capacitor at the Input

and Output

• Thermal Shutdown

• 0.1μA shutdown Current

• Small 8-Bump Thin DSBGA Package

APPLICATIONS

• LCD Bias Supplies

• White LED Back-Lighting

• Handheld Devices

• Digital Cameras

• Portable Applications

DESCRIPTION

The LM3501 is a fixed-frequency step-up DC/DC

converter that is ideal for driving white LEDs for

display backlighting and other lighting functions. With fully integrated synchronous switching (no external

schottky diode required) and a low feedback voltage

(515 mV), power efficiency of the LM3501 circuit has

been optimized for lighting applications in wireless

phones and other portable products (single cell Li-Ion

or 3-cell NiMH battery supplies). The LM3501

operates with a fixed 1 MHz switching frequency. When used with ceramic input and output capacitors,

the LM3501 provides a small, low-noise, low-cost

solution.