Datasheet ADP2140 (Analog Devices) - 2

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ADP2140 Data Sheet TABLE OF CONTENTS
Features .. 1 Short-Circuit Protection.. 20 Applications ... 1 Undervoltage Lockout ... 20 General Description ... 1 Thermal Protection .. 20 Typical Application Circuits .. 1 Soft Start .. 20 Revision History ... 2 Current Limit .. 20 Specifications ... 3 Power-Good Pin ... 20 Recommended Specifications: Capacitors and Inductor .. 4 LDO Section.. 20 Absolute Maximum Ratings .. 5 Applications Information .. 21 Thermal Data .. 5 Power Sequencing .. 21 Thermal Resistance .. 5 Power-Good Function ... 24 ESD Caution .. 5 External Component Selection .. 24 Pin Configuration and Function Descriptions ... 6 Selecting the Inductor .. 24 Typical Performance Characteristics ... 7 Output Capacitor .. 24 Buck Output .. 7 Input Capacitor ... 24 LDO Output .. 14 Efficiency ... 25 Theory of Operation .. 19 Recommended Buck External Components .. 25 Buck Section .. 19 LDO Capacitor Selection .. 26 Control Scheme .. 19 LDO as a Postregulator to Reduce Buck Output Noise .. 26 PWM Operation ... 19 Thermal Considerations .. 28 PSM Operation ... 19 PCB Layout Considerations .. 29 Pulse Skipping Threshold .. 19 Outline Dimensions ... 30 Selected Features ... 20 Ordering Guide .. 30
REVISION HISTORY 9/12—Rev. 0 to Rev. A
Updated Outline Dimensions ... 30 Changes to Ordering Guide .. 30
6/10—Revision 0: Initial Version
Rev. A | Page 2 of 32 Document Outline Features Applications General Description Typical Application Circuits Revision History Specifications Recommended Specifications: Capacitors and Inductor Pin Configuration and Function Descriptions Typical Performance Characteristics Buck Output LDO Output Theory of Operation Buck Section Control Scheme PWM Operation PSM Operation Pulse Skipping Threshold Selected Features Short-Circuit Protection Undervoltage Lockout Thermal Protection Soft Start Current Limit Power-Good Pin LDO Section Applications Information Power Sequencing Power-Good Function External Component Selection Selecting the Inductor Output Capacitor Input Capacitor Efficiency Power Switch Conduction Losses Inductor Losses Switching Losses Transition Losses Recommended Buck External Components LDO Capacitor Selection Output Capacitor Input Bypass Capacitor Input and Output Capacitor Properties LDO as a Postregulator to Reduce Buck Output Noise Thermal Considerations PCB Layout Considerations Outline Dimensions Ordering Guide