General 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 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 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.
●Features
●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 micro SMD package
