LM3500

LM3500 www.ti.com SNVS231G – AUGUST 2003 – REVISED MAY 2013 LM3500 Synchronous Step-up DC/DC Converter for White LED Applications Check for Samples: LM3500 FEATURES 1 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 Internal Output Over-Voltage Protection (OVP) Circuitry, with no External Zener Diode Required – LM3500-16: 15.5V OVP; LM3500-21: 20.5V OVP. True Shutdown Isolation Input Undervoltage Lockout Requires Only Small Ceramic Capacitors at the Input and Output Thermal Shutdown 0.1µA Shutdown Current Small 8-Bump Thin DSBGA Package APPLICATIONS LCD Bias Supplies White LED Backlighting Handheld Devices Digital Cameras Portable Applications DESCRIPTION The LM3500 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 intergrated synchronous switching (no external schottky diode required) and a low feedback voltage (500mV), power efficiency of the LM3500 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 LM3500 operates with a fixed 1MHz switching frequency. When used with ceramic input and output capacitors, the LM3500 provides a small, low-noise, low-cost solution. Typical ...