www.fairchildsemi.com

Datasheet preview, take a look at Datasheets before downloading (Data Sheet is available on manufacturer site)

www.fairchildsemi.com

FAN5609
LED Driver with Adaptive Charge Pump DC/DC Converter
Features
Parallel LED Driver Supports All Forward Voltages Adaptive VOUT Adjustment to the Highest Diode Voltage Internally Matched LED Current Sources No External Components Needed to Set LED Current Built-in Charge Pump has Three Modes of Operation: Linear Regulation VIN 4.2V 3/2 DC-DC Converter and Regulation 3.6V VIN 4.2V 2/1 DC-DC Converter and Regulation 2.7V VIN 3.6V Up to 86% Efficiency Low EMI, Low Ripple Up to 80mA Output Current (4 20mA) Built-in DAC for Digital or PWM Brightness Control Can be Duty Cycle Modulated between 0 to 18mA 2.7V to 5.5V Input Voltage Range ICC 2 A in Shutdown Mode 1MHz Operating Frequency Shutdown Isolates Output from Input Soft-Start Limits Inrush Current Short Circuit Protection Minimal External Components Needed Available in a 14-lead TSSOP Package Available in a 16-lead MLP Package

Applications
Cell Phones Handheld Computers PDA, DSC, MP3 Players Keyboard Backlight LED Displays

Description
The FAN5609 generates regulated output current from a battery with input voltage varying between 2.7V to 5.5V. Switch reconfiguration and fractional switching techniques are utilized to achieve high efficiency over the entire input voltage range. A proprietary internal circuitry continuously monitors each LED current loop and automatically adjusts the generated output DC voltage to the lowest minimum value required by the LED having the highest forward voltage. This adaptive nature of the FAN5609 eliminates the need for LED pre-selection (matching) and ensures operation at high efficiency. When the input voltage is sufficiently high to sustain the programmed current level in the LEDs, the FAN5609 re-configures itself to operate as a linear regulator, and the DC-DC converter is turned off. An internal two-bit digital to analog converter provides programmability of the output currents. Only two 0.1 F bucket capacitors and two 4.7 F input/output capacitors are needed for proper operation. Soft-start circuitry p
revents excessive current draw during power on. The device has built-in short circuit protection.

Typical Application
VOUT COUT

VIN CIN

VOUT VIN IN A

LED-

LED-

LED-

LEDCAPCAP2 CAP CAP CAP1

D A C

FAN5609
GND

IN B

CAP-

REV. 1.0.2 5/30/03

FAN5609 Datasheet Fairchild Download PDF

Add this permalink to your bookmarks for future download of FAN5609 datasheet

Permalink: http://datasheet.emcelettronica.com/fairchild/FAN5609

FAN5609 DATASHEET