Ultralow Profile, 500 mA, 6 MHz, Synchronous, Step-Down, DC-to-DC Converters Data Sheet ADP2126/ADP2127 FEATURES TYPICAL APPLICATIONS CIRCUIT 1.20 V and 1.26 V fixed output voltage options ADP2126/ Clock signal enable L ADP2127 1.0H INPUT OUTPUT Logic signal enable also available on certain models VOLTAGE A2 B1 VOLTAGE VIN SW 2.1V TO 5.5V 1.20V OR 1.26V 6 MHz operating frequency C IN C Spread spectrum frequency modulation to reduce EMI OUT 2.2F 2.2F C2 GND FB C1 500 mA continuous output current Input voltage: 2.1 V to 5.5 V EXTCLK MODE B2 A1 0.3 A (typical) shutdown supply current Pin-selectable power-saving mode PWM Compatible with tiny multilayer inductors AUTO Internal synchronous rectifier OFF ON * ON Internal compensation OR OFF Internal soft start Output-to-ground short-circuit protection *LOGIC HIGH ENABLE IS ONLY AVAILABLE ON CERTAIN MODELS. Current-limit protection Figure 1. Undervoltage lockout Thermal shutdown protection 0.330 mm height (maximum), 6-ball BUMPED CHIP (ADP2126) 0.200 mm height (maximum), 6-pad EWLP (ADP2127) APPLICATIONS Mobile phones Digital still/video cameras Digital audio Portable equipment Camera modules Image stabilization systems GENERAL DESCRIPTION The ADP2126/ADP2127 are high frequency, step-down, dc-to- The ADP2126/ADP2127 are enabled by a 6 MHz to 27 MHz dc converters optimized for portable applications in which board external clock signal applied to the EXTCLK pin. Certain models area and battery life are critical constraints. The fixed 6 MHz can also be enabled with a logic high signal. When the external clock operating frequency enables the use of tiny ceramic inductors is not switching and in a low logic state, the ADP2126/ADP2127 and capacitors and the regulators use spread spectrum frequency stop regulating and shut down to draw less than 0.3 A (typical) modulation to reduce EMI. Additionally, synchronous rectification from the source. improves efficiency and results in fewer external components. The ADP2126/ADP2127 have an input voltage range of 2.1 V to At high load currents, the ADP2126/ADP2127 use a voltage 5.5 V, allowing the use of single Li+/Li polymer cell, three-cell regulating pulse-width modulation (PWM) mode that maintains alkaline, NiMH cell, and other standard power sources. The a constant frequency with excellent stability and transient response. ADP2126/ADP2127 are internally compensated to minimize Light load operation is determined by the state of the MODE pin. external components and can source up to 500 mA. Other key In forced PWM mode, the converter continues operating in PWM features, such as cycle-by-cycle peak current limit, soft start, for light loads. Under light load conditions in auto mode, the undervoltage lockout (UVLO), output-to-ground short-circuit ADP2126/ADP2127 automatically enter a power-saving mode, protection, and thermal shutdown provide protection for internal which uses pulse frequency modulation (PFM) to reduce the and external circuit components. effective switching frequency, thus ensuring the longest battery life in portable applications. Rev. B 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 20112012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 09658-001ADP2126/ADP2127 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 External Clock (EXTCLK) Enable........................................... 11 Applications....................................................................................... 1 Spread Spectrum Oscillator ...................................................... 12 Typical Applications Circuit............................................................ 1 Mode Selection ........................................................................... 12 General Description ......................................................................... 1 Internal Control Features .......................................................... 12 Revision History ............................................................................... 2 Protection Features .................................................................... 13 Specifications..................................................................................... 3 Timing Constraints .................................................................... 13 Timing Diagrams.......................................................................... 4 Applications Information .............................................................. 14 Absolute Maximum Ratings............................................................ 5 Inductor Selection ...................................................................... 14 Thermal Considerations.............................................................. 5 Input Capacitor Selection.......................................................... 14 Thermal Resistance ...................................................................... 5 Output Capacitor Selection....................................................... 15 ESD Caution.................................................................................. 5 Thermal Considerations............................................................ 15 Pin Configuration and Function Descriptions............................. 6 PCB Layout Guidelines.................................................................. 16 Typical Performance Characteristics ............................................. 7 Outline Dimensions....................................................................... 17 Theory of Operation ...................................................................... 11 Ordering Guide .......................................................................... 18 Overview...................................................................................... 11 REVISION HISTORY 3/12Rev. A to Rev. B 5/11Rev. 0 to Rev. A Changes to Figure 35...................................................................... 17 Combined Figure 1 and Figure 2 Renumbered Sequentially..... 1 Changes to Undervoltage Lockout (UVLO) Section, 5/11Revision 0: Initial Version Added Figure 29, Renumbered Sequentially .............................. 13 Changes to Table 6.......................................................................... 14 Changes to Ordering Guide .......................................................... 18 Rev. B Page 2 of 20