April 2005
FAN2001/FAN2002
1A High-Efficiency Step-Down DC-DC Converter
Features
■ 96% Efficiency, Synchronous Operation
■ Adjustable Output Voltage Options from 0.8V to VIN
■ 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
CIN
10µF
VIN
1
PGND
2
EN 3
P1
(AGND)
SW
6
3.3µH
5 NC
R1 5KΩ
FB
4
R2 10KΩ
FAN2001
VOUT
1.2V (1A)
COUT
2 x 10µF
R1
VOUT
1.2V (1A)
R2
5KΩ
10KΩ
FB
1
PGND
2
L1 SW
3
3.3µH
2 x 10µF
P1
(AGND)
EN
6
5 VIN
PVIN
4
10µF
FAN2002
Figure 1. Typical Application
FAN2001/FAN2002 Rev. 1.0.2
1
©2005 Fairchild Semiconductor Corporation
www.fairchildsemi.com