Low Profile, 500 mA, 6 MHz, Synchronous, Step-Down, DC-to-DC Converter ADP2125 FEATURES GENERAL DESCRIPTION 1.26 V fixed output voltage The ADP2125 is a high frequency, step-down, dc-to-dc Clock signal enable converter optimized for portable applications in which board 6 MHz (maximum) operating frequency area and battery life are critical constraints. Fixed frequency 500 mA continuous output current operation at 6 MHz enables the use of tiny ceramic inductors Input voltage: 2.1 V to 5.5 V and capacitors. Additionally, the synchronous rectification 0.3 A (typical) shutdown supply current improves efficiency and results in fewer external components. Compatible with tiny multilayer inductors Over all load currents, the device uses a voltage regulating Internal synchronous rectifier pulse-width modulation (PWM) mode that maintains a Internal compensation constant frequency with excellent stability and transient Internal soft start response. The ADP2125 is enabled by a 6 MHz to 27 MHz Output-to-ground short-circuit protection external clock signal applied to the EXTCLK pin. When the Current-limit protection external clock is not switching and in a low state (EXTCLK Undervoltage lockout 0.5 V), the input is disconnected from the output and draws less Thermal shutdown protection than 0.3 A (typical) from the source. Ultrasmall, 0.405 mm height (maximum), 6-ball BUMPED CHIP The ADP2125 has an input voltage range of 2.1 V to 5.5 V, APPLICATIONS allowing the use of single Li+/Li polymer cell, three-cell alkaline, NiMH cell, and other standard power sources. The Mobile phones ADP2125 is internally compensated to minimize external Digital still/video cameras components and can source up to 500 mA. Other key features Digital audio such as cycle-by-cycle peak current limit, soft start, undervoltage Portable equipment lockout (UVLO), output-to-ground short-circuit protection, and Camera modules thermal shutdown provide protection for internal and external Image stabilization systems circuit components. TYPICAL APPLICATION CIRCUIT L ADP2125 OUTPUT INPUT 1.5H VOLTAGE VOLTAGE A2 VIN SW B1 1.26V 2.1V TO 5.5V C IN C 2.2F OUT 4.7F C2 GND FB C1 EXTCLK NC B2 A1 NC = NO CONNECT OFF ON Figure 1. 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. 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Trademarks and registered trademarks are the property of their respective owners. 08774-002ADP2125 TABLE OF CONTENTS Features .............................................................................................. 1 Overview ..................................................................................... 10 Applications....................................................................................... 1 External Clock (EXTCLK) Enable........................................... 10 General Description ......................................................................... 1 Internal Control Features .......................................................... 10 Typical Application Circuit ............................................................. 1 Protection Features .................................................................... 11 Revision History ............................................................................... 2 Timing Constraints .................................................................... 11 Specifications..................................................................................... 3 Applications Information .............................................................. 12 Timing Diagram ........................................................................... 4 Inductor Selection ...................................................................... 12 Absolute Maximum Ratings............................................................ 5 Input Capacitor Selection.......................................................... 12 Thermal Considerations.............................................................. 5 Output Capacitor Selection....................................................... 13 Thermal Resistance ...................................................................... 5 Thermal Limit Calculations...................................................... 13 ESD Caution.................................................................................. 5 PCB Layout Guidelines.................................................................. 14 Pin Configuration and Function Descriptions............................. 6 Outline Dimensions....................................................................... 15 Typical Performance Characteristics ............................................. 7 Ordering Guide .......................................................................... 15 Theory of Operation ...................................................................... 10 REVISION HISTORY 5/11Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 15 9/10Revision 0: Initial Version Rev. A Page 2 of 16