FAN5333A Datasheet, PDF (1/11 Pages) Fairchild Semiconductor – High Efficiency, High Current Serial LED Driver with 30V Integrated Switch

August 2005
FAN5333A/FAN5333B
High Efficiency, High Current Serial LED Driver with 30V
Integrated Switch
Features
■ 1.5MHz Switching Frequency
■ Low Noise
■ Adjustable Output Voltage
■ Up to 1.5A Peak Switch Current
■ 1.5W Output Power Capability
■ Low Shutdown Current: <1µA
■ Cycle-by-Cycle Current Limit
■ Low Feedback Voltage
■ Over-Voltage Protection
■ Fixed-Frequency PWM Operation
■ Internal Compensation
■ FAN5333A has 110mV Feedback Voltage
■ FAN5333B has 315mV Feedback Voltage
■ Thermal Shutdown
■ 5-Lead SOT23 Package
Applications
■ Cell Phones
■ PDAs
■ Handheld Equipment
■ Display Bias
■ LED Bias
■ Flash LED
Description
The FAN5333A/FAN5333B is a general purpose LED driver that
features fixed frequency mode operation and an integrated FET
switch. The device’s high output power makes it suitable to drive
flash LEDs in serial connections. This device is designed to
operate at high switching frequencies in order to minimize
switching noise measured at the battery terminal of hand-held
communications equipment. Quiescent current in both normal
and shutdown mode is designed to be minimal in order to
extend battery life. Normal 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 1.5A. The FAN5333A/FAN5333B is available in
a 5-lead SOT23 package.
Typical Application
V_IN
4.7µF ^CIN
to
10µF
L
6.8µH to 10µH
5
VIN
SW ¹
BAT54
0.1µF
to
2.2µF
C_OUT
I_LED
I_LED1
V_OUT
I_LED2
3
FB
ON
OFF
4 _SHDN
2
GND
R
R1
R2
Figure 1. Typical Application Diagram
©2005 Fairchild Semiconductor Corporation
1
FAN5333A/FAN5333B Rev. 1.0.1
www.fairchildsemi.com