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link to page 43 link to page 44 link to page 44 link to page 45 link to page 45 link to page 45 link to page 46 link to page 46 link to page 46 link to page 47 link to page 48 link to page 49 link to page 50 link to page 50 link to page 50 LTC3886/LTC3886-1 TABLE OF CONTENTS Features ... 1 Responses to VOUT and IOUT Faults ..27 Power Conversion ..1 Output Overvoltage Fault Response ...27 Applications .. 1 Output Undervoltage Response ...28 Typical Application .. 1 Peak Output Overcurrent Fault Response ...28 Description.. 1 Responses to Timing Faults ..28 Table of Contents .. 2 Responses to VIN OV Faults ..28 Absolute Maximum Ratings .. 4 Responses to OT/UT Faults ...28 Order Information .. 4 Internal Overtemperature Fault/Warn Pin Configuration .. 4 Response ..28 Electrical Characteristics ... 5 External Overtemperature and Typical Performance Characteristics ..10 Undertemperature Fault Response ..29 Pin Functions ..13 Responses to External Faults ...29 Block Diagram ...15 Fault Logging ..29 Operation...16 Bus Timeout Protection ..29 Overview ... 16 Similarity Between PMBus, SMBus and I2C Main Control Loop .. 16 2-Wire Interface ..30 EEPROM ... 17 PMBus Serial Digital Interface ..30 Power-Up and Initialization ... 17 PMBus Command Summary ..35 Soft-Start .. 18 PMBus Commands ...35 Time-Based Sequencing ... 18 *Data Format ..40 Event-Based Sequencing .. 19 Applications Information ..41 Shutdown ... 19 Current Limit Programming .. 41 Light-Load Current Operation ...20 I + – SENSE and ISENSE Pins ... 41 PWM Loop Compensation ..20 Low Value Resistor Current Sensing ...42 Switching Frequency and Phase ...20 Inductor DCR Current Sensing ..43 Output Voltage Sensing ..21 Slope Compensation and Inductor Peak Current ..44 Output Current Sensing ..21 Inductor Value Calculation ..44 Input Current Sensing ...21 Inductor Core Selection ..45 PolyPhase Load Sharing ...22 Power MOSFET and Optional Schottky Diode External/Internal Temperature Sense ..22 Selection ...45 RCONFIG (Resistor Configuration) Pins ..23 CIN and COUT Selection ...46 Fault Handling ...23 Variable Delay Time, Soft-Start and Output Status Registers and ALERT Masking ... 24 Voltage Ramping ..46 Mapping Faults to FAULT Pins ..26 Digital Servo Mode ...47 Power Good Pins ..26 Soft Off (Sequenced Off) ..48 CRC Protection ..26 INTVCC Regulator ..49 Serial Interface ...26 Topside MOSFET Driver Supply (CB, DB) ..50 Communication Protection ..27 Undervoltage Lockout ...50 Device Addressing ..27 Fault Indications ...50 Rev F 2 For more information www.analog.com Document Outline Table of Contents Features Power Conversion Applications Typical Application Description Table of Contents Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM Power-Up and Initialization Soft-Start Time-Based Sequencing Event-Based Sequencing Shutdown Light-Load Current Operation PWM Loop Compensation Switching Frequency and Phase Output Voltage Sensing Output Current Sensing Input Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Handling Status Registers and ALERT Masking Mapping Faults to FAULT Pins Power Good Pins CRC Protection Serial Interface Communication Protection Device Addressing Responses to VOUT and IOUT Faults Output Overvoltage Fault Response Output Undervoltage Response Peak Output Overcurrent Fault Response Responses to Timing Faults Responses to VIN OV Faults Responses to OT/UT Faults Internal Overtemperature Fault/Warn Response External Overtemperature and Undertemperature Fault Response Responses to External Faults Fault Logging Bus Timeout Protection Similarity Between PMBus, SMBus and I2C 2-Wire Interface PMBus Serial Digital Interface PMBus Command Summary PMBus Commands *Data Format Applications Information Current Limit Programming ISENSE+ and ISENSE– Pins Low Value Resistor Current Sensing Inductor DCR Current Sensing Slope Compensation and Inductor Peak Current Inductor Value Calculation Inductor Core Selection Power MOSFET and Optional Schottky Diode Selection CIN and COUT Selection Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) INTVCC Regulator Topside MOSFET Driver Supply (CB, DB) Undervoltage Lockout Fault Indications Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations External Temperature Sense Derating EEPROM Retention at Temperature Input Current Sense Amplifier External Resistor Configuration Pins (RCONFIG) Voltage Selection Frequency Selection Phase Selection Address Selection Using RCONFIG Efficiency Considerations Programmable Loop Compensation Checking Transient Response PolyPhase Configuration PC Board Layout Checklist PC Board Layout Debugging Design Example Additional Design Checks Connecting the USB to I2C/SMBus/PMBus Adapter to the LTC3886 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration COMMANDS On/Off/Margin ON_OFF_CONFIG PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits For EnableMfrVoffThreshold = 0 For EnableMfrVoffThreshold = 1 Output Current and Limits Input Current and Limits Temperature External Temperature Calibration Timing Timing—On Sequence/Ramp Timing—Off Sequence/Ramp Precondition for Restart Fault Response Fault Responses All Faults Fault Responses Input Voltage Fault Responses Output Voltage Fault Responses Output Current Fault Responses IC Temperature Fault Responses External Temperature Fault Sharing Fault Sharing Propagation Fault Sharing Response Scratchpad Identification Fault Warning and Status Telemetry EEPROM Memory Commands Store/Restore Fault Logging Fault Log Operation Block Memory Write/Read Typical Applications Package Description Revision History Typical Application Related Parts