Datasheet ADP3051 (Analog Devices)

500 mA PWM Step-Down DC-DC with Synchronous Rectifier ADP3051 FEATURES GENERAL DESCRIPTION Current mode control for simple loop compensation
The ADP3051 is a low noise, current mode, pulse width modu-
Input voltage range: 2.7 V to 5.5 V
lator (PWM) step-down converter capable of supplying over
Output voltage range: 0.8 V to 5.5 V
500 mA to output voltages as low as 0.8 V. This device integrates
Tri-Mode™ operation for high efficiency
a low resistance power switch and synchronous rectifier, provid-
550 kHz PWM operating frequency
ing excellent efficiency over the entire output voltage range and
High accuracy over line, load, and temperature
eliminating the need for a large and costly external Schottky
Micropower shutdown mode
rectifier. Its 550 kHz switching frequency permits the use of
Space-saving MSOP-8 package
small external components.
APPLICATIONS
Current mode control and external compensation allow the regulator to be easily optimized for a wide range of operating
Li-ion powered handhelds
conditions. The ADP3051 operates at a constant 550 kHz
MP3 players
frequency at medium to heavy loads; it smoothly transitions
PDAs and palmtops
into Tri-Mode operation to save power at light loads. A pin-
Consumer electronics
controlled micropower shutdown mode is also included. The ADP3051’s 2.7 V to 5.5 V input operating range makes it ideal for both battery-powered applications as well as those with 3.3 V or 5 V supply buses. It is available in a space-saving, 8-lead MSOP package.
TYPICAL APPLICATION CIRCUIT ADP3051 V VOUT 1.8V IN 3.3V 10
µ
H 4 IN SW 3 7 SHDN 12.5k
Ω
6 COMP FB 10
µ
F 5 10
µ
F 10k
Ω
10k
Ω
27pF PGND GND 270pF 2 8
04768-0-001 Figure 1.
Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. or otherwise under any patent or patent rights of Analog Devices. Trademarks and Tel: 781.329.4700 www.analog.com registered trademarks are the property of their respective owners. Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES APPLICATIONS GENERAL DESCRIP TYPICAL APPLICATION CIRCUIT TABLE OF CONTENTS SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION PWM CONTROL MODE TRI-MODE OPERATION 100% DUTY CYCLE OPERATION SHUTDOWN UNDERVOLTAGE LOCKOUT (UVLO) SHORT-CIRCUIT PROTECTION AND RECOVERY APPLICATIONS RECOMMENDED COMPONENTS DESIGN PROCEDURE Setting the Output Voltage Inductor Selection OUTPUT CAPACITOR SELECTION Input Capacitor Selection Compensation Design CIRCUIT BOARD LAYOUT CONSIDERATIONS OUTLINE DIMENSIONS ORDERING GUIDE