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.