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120 LTC3889 TABLE OF CONTENTS Phase-Locked Loop and Frequency Output Current and Limits ..80 Synchronization ..50 Input Current and Limits ..82 Minimum On-Time Considerations.. 51 Temperature ..83 External Temperature Sense ... 51 External Temperature Calibration..83 Derating EEPROM Retention at Temperature ..52 Timing ..84 Input Current Sense Amplifier ...53 Timing—On Sequence/Ramp ...84 External Resistor Configuration Pins (RCONFIG) ..53 Timing—Off Sequence/Ramp ..85 Voltage Selection ..53 Precondition for Restart ...86 Frequency Selection ..54 Fault Response ...87 Phase Selection ..55 Fault Responses Al Faults ..87 Address Selection Using RCONFIG ...55 Fault Responses Input Voltage ...87 Efficiency Considerations ...55 Fault Responses Output Voltage ...87 Programmable Loop Compensation ...56 Fault Responses Output Current ...91 Checking Transient Response ...57 Fault Responses IC Temperature ..92 PolyPhase Configuration ..58 Fault Responses External Temperature ...93 PC Board Layout Checklist ...60 Fault Sharing ...94 PC Board Layout Debugging ...60 Fault Sharing Propagation ..94 Design Example ..62 Fault Sharing Response ..96 Additional Design Checks ...63 Scratchpad ...96 Connecting the USB to I2C/SMBus/PMBus Adapter to Identification ...97 the LTC3889 In System ..63 Fault Warning and Status ..98 LTpowerPlay: An Interactive GUI for Digital Power .64 Telemetry .. 105 PMBus Communication and Command Processing 65 EEPROM Memory Commands .. 109 PMBus Command Details ...67 Store/Restore ... 109 Addressing and Write Protect ...67 Fault Logging .. 110 General Configuration COMMANDS ..69 Fault Log Operation .. 110 On/Off/Margin ..70 Block Memory Write/Read.. 115 PWM Configuration ..72 Typical Applications .. 116 Voltage ..76 Package Description ... 119 Input Voltage and Limits ...76 Typical Application ... 120 Output Voltage and Limits ..77 Related Parts .. 120 Rev. 0 For more information www.analog.com 3 Document Outline Table of Contents Features 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 CRC Protection 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 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 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) DRVCC 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 LTC3889 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 PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits 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 Typical Application Related Parts