Datasheet ADP2442 (Analog Devices) - 2

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ADP2442 Data Sheet TABLE OF CONTENTS
Features .. 1 Thermal Shutdown .. 18 Applications ... 1 Applications Information .. 19 General Description ... 1 ADIsimPower Design Tool ... 19 Typical Circuit Configuration ... 1 Selecting the Output Voltage .. 19 Revision History ... 2 Setting the Switching Frequency .. 19 Specifications ... 3 External Component Selection .. 20 Absolute Maximum Ratings .. 5 Boost Capacitor .. 22 Thermal Resistance .. 5 VCC Capacitor.. 22 ESD Caution .. 5 Loop Compensation .. 22 Pin Configuration and Function Descriptions ... 6 Large Signal Analysis of the Loop Compensation ... 22 Typical Performance Characteristics ... 7 Design Example .. 24 Efficiency in Forced Fixed Frequency Mode .. 7 Configuration and Components Selection ... 24 Efficiency in Pulse Skip Mode .. 8 System Configuration .. 25 Internal Block Diagram ... 15 Typical Application Circuits ... 26 Theory of Operation .. 16 Design Example .. 26 Control Architecure ... 16 Other Typical Circuit Configurations ... 27 Adjustable Frequency ... 17 Power Dissipation and Thermal Considerations ... 31 Power Good ... 17 Power Dissipation... 31 Mode of Operation ... 17 Thermal Considerations .. 31 External Synchronization .. 17 Evaluation Board Thermal Performance .. 32 Soft Start .. 17 Circuit Board Layout Recommendations ... 33 Undervoltage Lockout ... 17 Outline Dimensions ... 34 Precision Enable/Shutdown .. 17 Ordering Guide .. 34 Current-Limit and Short-Circuit Protection .. 18
REVISION HISTORY 8/15—Rev. A to Rev. B
Changes to Figure 51 .. 15
5/14—Rev. 0 to Rev. A
Change to Features Section ... 1
11/12—Revision 0: Initial Version
Rev. B | Page 2 of 36 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TYPICAL CIRCUIT CONFIGURATION REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS EFFICIENCY IN FORCED FIXED FREQUENCY MODE EFFICIENCY IN PULSE SKIP MODE INTERNAL BLOCK DIAGRAM THEORY OF OPERATION CONTROL ARCHITECURE Fixed Frequency Mode Pulse Skip Mode ADJUSTABLE FREQUENCY POWER GOOD MODE OF OPERATION EXTERNAL SYNCHRONIZATION SOFT START UNDERVOLTAGE LOCKOUT PRECISION ENABLE/SHUTDOWN CURRENT-LIMIT AND SHORT-CIRCUIT PROTECTION THERMAL SHUTDOWN APPLICATIONS INFORMATION ADIsimPOWER DESIGN TOOL SELECTING THE OUTPUT VOLTAGE SETTING THE SWITCHING FREQUENCY EXTERNAL COMPONENT SELECTION Input Capacitor Selection Inductor Selection Output Capacitor Selection BOOST CAPACITOR VCC CAPACITOR LOOP COMPENSATION LARGE SIGNAL ANALYSIS OF THE LOOP COMPENSATION DESIGN EXAMPLE CONFIGURATION AND COMPONENTS SELECTION Resistor Divider Switching Frequency Inductor Selection Input Capacitor Selection Output Capacitor Selection Compensation Selection SYSTEM CONFIGURATION TYPICAL APPLICATION CIRCUITS DESIGN EXAMPLE OTHER TYPICAL CIRCUIT CONFIGURATIONS POWER DISSIPATION AND THERMAL CONSIDERATIONS POWER DISSIPATION Inductor Losses Power Switch Conduction Losses Switching Losses Transition Losses THERMAL CONSIDERATIONS EVALUATION BOARD THERMAL PERFORMANCE CIRCUIT BOARD LAYOUT RECOMMENDATIONS OUTLINE DIMENSIONS ORDERING GUIDE