Data Sheet

©2004 Fairchild Semiconductor Corporation 1 www.fairchildsemi.com
August 2005
FAN5331 Rev. 1.0.1
FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
FAN5331
High Efficiency Serial LED Driver and OLED Supply with
20V Integrated Switch
Features
■ 1.6MHz Switching Frequency
■ Low Noise
■ Low R
DS(ON)
: 0.5 Ω
■ Adjustable Output Voltage
■ 1A Peak Switch Current
■ 1W Output Power Capability
■ Low Shutdown Current: <1µA
■ Cycle-by-Cycle Current Limit
■ Over-Voltage Protection
■ Fixed-Frequency PWM Operation
■ Internal Compensation
■ 5-lead SOT-23 Package
Applications
■ Cell Phones
■ PDAs
■ Handheld Equipment
■ Display Bias
■ LED Bias
Description
The FAN5331 is a general purpose, fixed-frequency boost con-
verter designed to operate at high switching frequencies in
order to minimize switching noise measured at the battery ter-
minal of hand-held communications equipment. Quiescent cur-
rent in normal mode of operation as well as in shutdown mode
is designed to be minimal in order to extend battery life. Normal
mode of operation or shutdown mode can be selected by a logic
level shutdown circuitry.
The low ON-resistance of the internal N-channel switch ensures
high efficiency and low power dissipation. A cycle-by-cycle cur-
rent limit circuit keeps the peak current of the switch below a
typical value of 1A. The FAN5331 is available in a 5-lead SOT-
23 package.
Typical Application
Figure 1. Typical Application Diagram
SHDN
V
IN
V
OUT
R1
R2
GND
V
IN
FB
SW
FAN5331
C
F
C
IN
10µH
1
3
2
4
5
4.7µF
120pF
C
OUT
L
BAT54
4.7µF
2.7V to 5.5V
ON
OFF