LM3501 - National Semiconductor

LM3501 Synchronous Step-up DC/DC Converter

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 intergrated 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 wirel.

Features

n Synchronous rectification, high efficiency and no external schottky diode required n Uses small surface mount components n Can drive 2-5 white LEDs in series (may function with more low VF LEDs) n 2.7V to 7V input range n True shutdown isolation, no LED leakage current n DC voltage LED current control n Input undervoltage lockout n Internal output over-voltage protection (OVP) circuitry, with no external zener diode required LM3501-16: 15.5V OVP; LM3501-21: 20.5V OVP. n Requires only a small 16V (LM3501-16) or 25V (LM3501-21) ceramic capacitor at the input and output n Thermal Shutdown n 0.1.