LM3503_06 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – Dual-Display Constant Current LED Driver with Analog Brightness Control

August 2006
LM3503
Dual-Display Constant Current LED Driver with Analog
Brightness Control
General Description
The LM3503 is a white LED driver for lighting applications.
For dual display backlighting applications, the LM3503 pro-
vides a complete solution. The LM3503 contains two internal
white LED current bypass FET (Field Effect Transistor)
switches. The white LED current can be adjusted with a DC
voltage from a digital to analog converter or RC filtered PWM
(pulse-width-modulated) signal at the Cntrl pin.
With no external compensation, cycle-by-cycle current limit,
output over-voltage protection, input under-voltage protec-
tion, and dynamic white LED current control capability, the
LM3503 offers superior performance over other step-up
white LED drivers.
Features
n Drives up to 4, 6, 8 or 10 White LEDs for Dual Display
Backlighting
n >80% Peak Efficiency
n Output Voltage Protection Options: 16V, 25V, 35V & 44V
n Input Under-Voltage Protection
n Internal Soft Start Eliminates Inrush Current
n 1 MHz Constant Switching Frequency
n Analog Brightness Control
n Wide Input Voltage Range: 2.5V to 5.5V
n Low Profile Packages: <1 mm Height
— 10 Bump MicroSMD
— 16 Pin LLP
Applications
n Dual Display Backlighting in Portable devices
n Cellular Phones and PDAs
Typical Application
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