Datasheet LT8228 (Analog Devices) - 2

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TABLE OF CONTENTS Features ... 1
RSET2P Selection for V2 Output Current
Applications .. 1
Limit (Buck Mode) ...36
Typical Application .. 1
RSET2N Selection for V2 Input Current
Description.. 1
Limit (Boost Mode) ..37
Absolute Maximum Ratings .. 3
RMON2 Selection for V2 Current Monitoring ..38
Order Information .. 3
RSNS1 and RIN1 Selection ..38
Pin Configuration .. 3
RSET1P Selection for V1 Input Current
Electrical Characteristics ... 4
Limit (Buck Mode) ...39
Typical Performance Characteristics ... 9
RSET1N Selection for V1 Output Current Buck Efficiency and Operation ..9 Limit (Boost Mode) ..40
Typical Performance Characteristics ..11
RMON1 Selection for V1 Current Monitoring ..41 Boost Efficiency and Operation ... 11 Output Voltage, Input Undervoltage and Output ENABLE, Supply Current and VCC ...13 Overvoltage Programming .. 41 SS Current, Frequency, Thresholds and Driver .. 15 Power MOSFET Selection and Efficiency Protection MOSFET Control er .. 15 Considerations ..42
Pin Functions ..16
Optional Schottky Diode (D2 and D3) Selection ...45
Block Diagram ...23
Top MOSFET Driver Supply (CBST, DBST) ..46
Operation...24
Power Path Capacitor Selection ..46 Overview ... 24 Loop Compensation ..48 Buck Mode Operation ... 24 Inrush Current Control ..49 Boost Mode Operation ..25 Boost Output Short Protection and Timer...50 V1 Protection MOSFET Control er Operation ..26 FAULT Conditions ..52 V2 Protection MOSFET Control er Operation ..28 Soft-Start ..53 Mode of Operation (DRXN) ...28 REPORT Feature ..53 Enable and Soft-Start (Enable and SS) ...29 Paral eling Multiple LT8228s ...56 Paral eling Multiple Control ers (ISHARE  BIAS, DRVCC, INTVCC and Power Dissipation ...57 and IGND) ...30 Thermal Shutdown ...58 BIAS Supply and VCC Regulators ..31 Pin Clearance/Creepage Consideration ...59 Strong Gate Drivers ..32 Efficiency Considerations ...59 Frequency Selection, Spread Spectrum and Phase- PC Board Layout Checklist ...59 Locked Loop (RT and SYNC) ..32 Design Example ..60 FAULT Monitoring and REPORT Feature ..32
Package Description ...67 Applications Information ..33 Typical Application ...68
Introduction ..33
Related Parts ..68
Programming the Switching Frequency ..33 Inductor Selection...34 RSNS2 and RIN2 Selection for Peak Inductor  Current ..35 Rev. 0 2 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Buck Efficiency and Operation Typical Performance Characteristics Boost Efficiency and Operation ENABLE, Supply Current and VCC SS Current, Frequency, Thresholds and Driver Protection MOSFET Controller Pin Functions Block Diagram Operation Overview Buck Mode Operation Boost Mode Operation V1 Protection MOSFET Controller Operation V2 Protection MOSFET Controller Operation Mode of Operation (DRXN) Enable and Soft-Start (Enable and SS) Paralleling Multiple Controllers (ISHARE AND IGND) BIAS Supply and VCC Regulators Strong Gate Drivers Frequency Selection, Spread Spectrum and Phase-Locked Loop (RT and SYNC) FAULT Monitoring and REPORT Feature Applications Information Introduction Programming the Switching Frequency Inductor Selection RSNS2 and RIN2 Selection for Peak Inductor Current RSET2P Selection for V2 Output Current Limit (Buck Mode) RSET2N Selection for V2 Input Current Limit (Boost Mode) RMON2 Selection for V2 Current Monitoring RSNS1 and RIN1 Selection RSET1P Selection for V1 Input Current Limit (Buck Mode) RSET1N Selection for V1 Output Current Limit (Boost Mode) RMON1 Selection for V1 Current Monitoring Output Voltage, Input Undervoltage and Output Overvoltage Programming Power MOSFET Selection and Efficiency Considerations Optional Schottky Diode (D2 and D3) Selection Top MOSFET Driver Supply (CBST, DBST) Power Path Capacitor Selection Loop Compensation Inrush Current Control Boost Output Short Protection and Timer FAULT Conditions Soft-Start REPORT Feature Paralleling Multiple LT8228s BIAS, DRVCC, INTVCC and Power Dissipation Thermal Shutdown Pin Clearance/Creepage Consideration Efficiency Considerations PC Board Layout Checklist Design Example Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts