2 A/3 A, 20 V, 700 kHz, Nonsynchronous Step-Down Regulators Data Sheet ADP2302/ADP2303 FEATURES TYPICAL APPLICATIONS CIRCUIT V IN Wide input voltage range: 3.0 V to 20 V VIN BST Maximum load current ADP2302/ 2 A for ADP2302 ADP2303 V OUT 3 A for ADP2303 PGOOD SW 1.5% output accuracy over temperature Output voltage down to 0.8 V ON OFF EN FB 700 kHz switching frequency Current-mode control architecture GND Automatic PFM/PWM mode Precision enable pin with hysteresis Figure 1. Typical Application Circuit Integrated high-side MOSFET Integrated bootstrap diode 100 Internal compensation and soft start Power-good output 90 Undervoltage lockout (UVLO) Overcurrent protection (OCP) Thermal shutdown (TSD) 80 8-lead SOIC package with exposed paddle Supported by ADIsimPower design tool 70 APPLICATIONS 60 Intermediate power rail conversion DC-to-DC point of load applications V = 3.3V OUT 50 Communications and networking V = 5.0V INDUCTOR: VLF10040T-4R7N5R4 OUT Industrial and instrumentation DIODE: SSB43L 40 Healthcare and medical 0 0.5 1.0 1.5 2.0 2.5 3.0 Consumer OUTPUT CURRENT (A) Figure 2. ADP2303 Efficiency vs. Output Current at V = 12 V IN GENERAL DESCRIPTION The ADP2302/ADP2303 are fixed frequency, current-mode The ADP2302/ADP2303 have integrated soft start circuitry to control, step-down, dc-to-dc regulators with an integrated prevent a large inrush current at power-up. The power-good power MOSFET. The ADP2302/ADP2303 can run from an signal can be used to sequence devices that have an enable input. input voltage of 3.0 V to 20 V, which makes them suitable for a The precision enable threshold voltage allows the part to be wide range of applications. The output voltage of the ADP2302/ easily sequenced from other input/output supplies. Other key ADP2303 can be down to 0.8 V for the adjustable version, while features include undervoltage lockout (UVLO), overvoltage the fixed output version is available in preset output voltage protection (OVP), thermal shutdown (TSD), and overcurrent options of 5.0 V, 3.3 V, and 2.5 V. The 700 kHz operating protection (OCP). frequency allows small inductor and ceramic capacitors to be The ADP2302/ADP2303 devices are available in the 8-lead, used, providing a compact solution. Current mode control o SOIC package with exposed paddle and are rated for the 40 C provides fast and stable line and load transient performance. o to +125 C junction temperature range. Rev. A 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 20102012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. EFFICIENCY (%) 08833-002 08833-001ADP2302/ADP2303 Data Sheet TABLE OF CONTENTS Overvoltage Protection (OVP) ................................................. 15 Features .............................................................................................. 1 Power Good ................................................................................ 15 Applications ....................................................................................... 1 Control Loop ............................................................................... 15 Typical Applications Circuit ............................................................ 1 Applications Information .............................................................. 16 General Description ......................................................................... 1 ADIsimPower Design Tool ....................................................... 16 Revision History ............................................................................... 2 Programming Output Voltage .................................................. 16 Specif icat ions ..................................................................................... 3 Voltage Conversion Limitations ............................................... 16 Absolute Maximum Ratings ............................................................ 4 Low Input Voltage Considerations .......................................... 17 Thermal Resistance ...................................................................... 4 Programming the Precision Enable ......................................... 17 ESD Caution .................................................................................. 4 Inductor ....................................................................................... 17 Pin Configuration and Function Descriptions ............................. 5 Catch Diode ................................................................................ 18 Typical Performance Characteristics ............................................. 6 Input Capacitor ........................................................................... 19 Functional Block Diagram ............................................................ 13 Output Capacitor........................................................................ 19 Theory of Operation ...................................................................... 14 Thermal Consideration ............................................................. 19 Basic Operation .......................................................................... 14 Design Example .............................................................................. 20 PWM Mode ................................................................................. 14 Catch Diode Selection ............................................................... 20 Power Saving Mode .................................................................... 14 Inductor Selection ...................................................................... 20 Bootstrap Circuitry .................................................................... 14 Output Capacitor Selection....................................................... 20 Precision Enable ......................................................................... 14 Resistive Voltage Divider Selection .......................................... 20 Integrated Soft Start ................................................................... 14 Circuit Board Layout Recommendations ................................... 22 Current Limit .............................................................................. 14 Typical Application Circuits ......................................................... 23 Short-Circuit Protection ............................................................ 14 Outline Dimensions ....................................................................... 26 Undervoltage Lockout (UVLO) ............................................... 15 Ordering Guide .......................................................................... 26 Thermal Shutdown (TSD) ......................................................... 15 REVISION HISTORY 6/12Rev. 0 to Rev. A Change to Features Section ............................................................. 1 Added ADIsimPower Design Tool Section ................................. 16 Change to Voltage Conversion Limitations Section .................. 16 Updated Outline Dimensions ....................................................... 26 Changes to Ordering Guide .......................................................... 26 7/10Revision 0: Initial Version Rev. A Page 2 of 28