©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

Features

■ 1.6MHz Switching Frequency

■ Low Noise

■ 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

R1

R2

GND

FB

SW

10µH

1

3

2

4

5

4.7

µF

120pF

L

BAT54

4.7

µF

2.7V to 5.5V

ON

OFF