FAN2001/FAN2002 Rev. 1.0.2

1

www.fairchildsemi.com

April 2005

©2005 Fairchild Semiconductor Corporation

FAN2001/FAN2002

1A High-Efficiency Step-Down DC-DC Converter

Features

■ 96% Efficiency, Synchronous Operation

■ 2.5V to 5.5V Input Voltage Range

■ Up to 1A Output Current

■ Fixed Frequency 1.3MHz PWM Operation

■ High Efficiency Power Save Mode

■ 100% Duty Cycle Low Dropout Operation

■ Soft Start

■ Output Over-Voltage Protection

■ Dynamic Output Voltage Positioning

■ 25µA Quiescent Current

■ Thermal Shutdown and Short Circuit Protection

■ Pb-Free 3x3mm 6-Lead MLP Package

Applications

■ Pocket PCs, PDAs

■ Cell Phones

■ Battery-Powered Portable Devices

■ Digital Cameras

■ Hard Disk Drives

■ Set-Top-Boxes

■ Point-of-Load Power

■ Notebook Computers

■ Communications Equipment

Description

Designed for use in battery-powered applications, the FAN2001/

FAN2002 is a high-efficiency, low-noise synchronous PWM cur-

rent mode and Pulse Skip (Power Save) mode DC-DC con-

verter. It can provide up to 1A of output current over a wide input

range from 2.5V to 5.5V. The output voltage can be externally

adjusted over a wide range of 0.8V to 5.5V by means of an

external voltage divider.

At moderate and light loads, pulse skipping modulation is used.

Dynamic voltage positioning is applied, and the output voltage is

shifted 0.8% above nominal value for increased headroom dur-

ing load transients. At higher loads the system automatically

switches over to current mode PWM control, operating at 1.3

MHz. A current mode control loop with fast transient response

ensures excellent line and load regulation. To achieve high effi-

ciency and ensure long battery life, the quiescent current is

reduced to 25µA in Power Save mode, and the supply current

drops below 1µA in shut-down mode. The FAN2001/FAN2002 is

available in a 3x3mm 6-lead MLP package.

Typical Application

Figure 1. Typical Application

1

2

3

6

5

4

FB

PGND

SW

EN

P1

(AGND)

L1

R2

R1

2 x 10

µF

3.3

µH

10

µF

10K

Ω

5K

Ω

1.2V (1A)

FAN2002

2 x 10

µF

10

µF

V

OUT

EN

SW

C

IN

C

OUT

1.2V (1A)

1

2

3

6

5

4

FB

PGND

NC

P1

(AGND)

3.3

µH

R1

10K

Ω

5K

Ω

R2

FAN2001