LM3520 Datasheet PDF | National Semiconductor

National Semiconductor LM3520

The LM3520 is a dual step-up DC/DC converter, designed to drive up to 5 white LEDs with a constant current and to power an organic LED display with a constant voltage. The LED current can be adjusted by applying a PWM signal to the EN pin. For higher efficiency the LM3520 operates with pulse frequency modulation (PFM) control scheme when the sub-display is enabled.

Part No.	LM3520
Datasheet	LM3520 Download
Manufacturer	National Semiconductor
Description	Integrated White LED Driver
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GENERAL DESCRIPTION

A single external resistor is used to set the maximum LED current. When Main display is enabled, the device is operating in PWM mode. Overvoltage protection circuitry and a 1MHz switching frequency allow for the use of small, low cost external components. Additional features include a low-side NFET switch that can turn off the LED string with no DC current path to ground. The LM3520 is available in a small 14-pin thermallyenchanced LLP package.

FEATURES

n Integrated OLED and white-LED driver n 80% efficiency n Drives up 5 LEDs at 20mA/3.6V and 4 LEDs at 30mA/3.6V for main-display n Up to 20V @ 50mA/3.6V for sub-display n True shutdown isolation n Small External Components n 1 MHz Switching Frequency n 23V OverVoltage Protection n Wide Input Voltage Range: 2.7V to 5.5V n Cycle-By-Cycle Current Limit n PWM Dimming Control n Low Profile 14-Pin LLP(3mm x 4mm x 0.8mm)

APPLICATIONS

n n n n n Flip-phones/Clam-shell Cellular Phones Handheld Devices High-fashion cellular pho...