GENERAL DESCRIPTION
The LED current is internally set to 20mA. Brightness control is achieved by applying a PWM signal on enable with frequencies up to 30kHz. The LM3519 features a proprietary PFM regulation architecture with switching frequencies between 2MHz to 8MHz, minimizing inductor size. Over-voltage protection circuitry and high frequency operation permit the use of low-cost small output capacitors. During shutdown, the output is disconnected from the input in order to avoid leakage current path through the LEDs to ground. The LM3519 is available in a tiny 6-pin SOT23 package. FEATURES
n n n n n n n n n Drives 2 to 4 LEDs at 20mA Up to 30kHz PWM Dimming Control Capability > 80% Peak Efficiency Up to 8MHz Switching Frequency Small External Components: 1µH - 3.3µH(typ.2.2µH) Inductor and 1µF Output Capacitor True Shutdown Isolation Over-Voltage Protection Wide Input Voltage Range: 2.7V to 5.5V Small Footprint SOT23-6 Package APPLICATIONS
n LCD, White LED Backlighting on Mobile Phones n Digital Still Cameras and PDAs n General Purpose LED Lighting in Handheld Devices Typical Application 20160201 FIGURE 1.
National Semiconductor
