www.fairchildsemi.com
REV. 1.0.1 12/2/04
Features
• Parallel LED Driver Supports all Forward Voltages
• Adaptive V
OUT
Adjustment to the Highest Diode Voltage
• Internally Matched LED Current Sources
• Built-in Charge Pump has Three Modes of Operation:
– 1X, 1.5X, and 2X Mode
• Up to 93% Efficiency
• Low EMI, Low Ripple
• Up to 120mA Output Current ( )
• External Resistor to Set Maximum (100%) LED Current
• Enable Input Can be Duty-Cycle-Modulated to Control
LED Current Level Between 0 and 100%
• 2.4V to 5.5V Input Voltage Range
•I
CC
< 1µA 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 4x4mm 16-lead MLP Package
Applications
• Cell Phones
• Handheld Computers
• PDA, DSC, MP3 Players
• Keyboard Backlight
• LED Displays
Description
The FAN5607 generates regulated output current from a bat-
tery 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 volt-
age. This adaptive nature of the FAN5607 eliminates the
need for LED pre-selection (matching) and ensures opera-
tion at high efficiency. When the input voltage is sufficiently
high to sustain the programmed current level in the LEDs,
the FAN5607 re-configures itself to operate as a linear regu-
lator, and the DC-DC converter is turned off. Only two 0.1µF
to 1µF bucket capacitors and two 4.7µF input/output capaci-
tors are needed for proper operation. LED current can be
programmed using an external resistor. The resistor sets the
maximum LED current and a PWM signal applied to the
enable pin can modulate that current level between 0mA
(off) and the maximum level.
Soft-start circuitry prevents excessive current draw during
power on. The device has built-in short circuit protection.
The device is available in 4x4mm 16-lead MLP package.
4
30mA×
FAN5607
LED Driver with Adaptive Charge Pump DC/DC
Converter
Typical Application
CAP1
CAP2
C
OUT
C
IN
LED-LED-LED-LED-
EN
V
OUT
V
OUT
V
IN
V
IN
R
SET
R
SET
GND
FAN5607
CAP+
CAP+
CAP-
CAP-
