link to page 1 link to page 1 link to page 1 link to page 1 link to page 5 link to page 5 link to page 5 link to page 6 link to page 10 link to page 13 link to page 15 link to page 16 link to page 18 link to page 18 link to page 18 link to page 18 link to page 19 link to page 19 link to page 21 link to page 21 link to page 21 link to page 21 link to page 22 link to page 22 link to page 22 link to page 22 link to page 23 link to page 23 link to page 23 link to page 24 link to page 24 link to page 24 link to page 24 link to page 25 link to page 25 link to page 25 link to page 25 link to page 26 link to page 26 link to page 26 link to page 26 link to page 26 link to page 27 link to page 27 link to page 27 link to page 27 link to page 28 link to page 28 link to page 28 link to page 28 link to page 28 link to page 28 link to page 29 link to page 29 link to page 31 link to page 31 link to page 34 link to page 35 link to page 39 link to page 39 link to page 39 link to page 40 link to page 40 link to page 40 link to page 45 link to page 45 link to page 45 link to page 47 link to page 47 link to page 47 link to page 48 link to page 49 link to page 49 link to page 51 link to page 52 link to page 52 link to page 53 link to page 54 link to page 54 link to page 54 link to page 56 link to page 56 link to page 57 link to page 60 link to page 61 link to page 61 link to page 62 link to page 62 link to page 63 LTC3888-1 TABLE OF CONTENTSFeatures ... 1 Hardwired PWM Response to IOUT Faults ..27 Applications .. 1 Hardwired PWM Response to Internal Typical Application .. 1 Temperature Faults ...28 Description.. 1 External Temperature Faults ...28 Absolute Maximum Ratings .. 5 Timing Faults ..28 Order Information .. 5 External Faults ..28 Pin Configuration .. 5 Higher-Level Fault Handling ..28 Electrical Characteristics ... 6 Status Registers and ALERT Masking ...29 Typical Performance Characteristics ..10 FAULT Pin I/O ..29 Pin Functions ..13 Fault Log Operation ..31 Block Diagram ...15 Fault Log Details ...31 Test Circuit ...16 Factory Default Operation ...34 Operation...18 Serial Interface ...35 Overview ... 18 Serial Bus Addressing ..39 About This Document ... 18 Serial Bus Timeout ...39 Major Product Features .. 18 Serial Communication Errors..39 Main Control Loop .. 19 PMBus Command Summary ..40 Power-Up and Initialization ... 19 PMBus Commands ...40 Testing Integrity of Output Voltage Sense ..21 Data Formats ..40 Analog Output Voltage Control ...21 Applications Information ..45 PMBus Output Voltage Control ...21 Efficiency Considerations ...45 Soft-Start ..21 Power Stage Selection and Interface ..45 Time-Based Output Sequencing ...22 Using The VDR Monitor ..47 Output Ramping Control ...22 Unused TSNS Inputs ..47 Voltage-Based Output Sequencing ...22 PWM Frequency and Inductor Selection ...47 Output Disable ..22 CIN Selection ...48 Minimum Output Disable Times ...23 COUT Selection ..49 Output Short Cycle ...23 Programmable Loop Compensation ...49 Switching Frequency and Phase ...23 PCB Layout Considerations .. 51 PolyPhase Load Sharing ... 24 Output Voltage Sensing ..52 Voltage Control Loop Compensation .. 24 Classical Analog Output Voltage Control ..52 Load Step Emulation ... 24 PMBus Output Voltage Control ...53 Input Supply Monitoring ... 24 Using Output Voltage Servo ..54 Output Voltage Sensing and Monitoring ...25 Soft-Start and Stop...54 Output Current Sensing and Monitoring ...25 Time-Based Output Sequencing and Ramping ...54 Temperature Sense ...25 Voltage-Based Output Sequencing ...56 Resistor Configuration Pins ..25 PWM Frequency Synchronization ...56 Internal EEPROM with CRC ...26 PolyPhase Operation and Load Sharing ..57 Fault Detection ..26 Resistor Configuration Pins ..60 Input Supply Faults ...26 Internal Regulator Outputs ..61 Hardwired PWM Response to Power IC Junction Temperature ...61 Stage Faults ..26 Derating EEPROM Retention at Temperature ..62 Hardwired PWM Response to Power Stage UV ..27 Configuring Open-Drain Pins ..62 Hardwired PWM Response to VOUT Faults ...27 PMBus Communication and Command Processing 63 Power Good Indication ...27 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 Pin Functions Block Diagram Test Circuit Operation Overview About This Document Major Product Features Main Control Loop Power-Up and Initialization Testing Integrity of Output Voltage Sense Analog Output Voltage Control PMBus Output Voltage Control Soft-Start Time-Based Output Sequencing Output Ramping Control Voltage-Based Output Sequencing Output Disable Minimum Output Disable Times Output Short Cycle Switching Frequency and Phase PolyPhase Load Sharing Voltage Control Loop Compensation Load Step Emulation Input Supply Monitoring Output Voltage Sensing and Monitoring Output Current Sensing and Monitoring Temperature Sense Resistor Configuration Pins Internal EEPROM with CRC Fault Detection Input Supply Faults Hardwired PWM Response to Power Stage Faults Hardwired PWM Response to Power Stage UV Hardwired PWM Response to VOUT Faults Power Good Indication Hardwired PWM Response to IOUT Faults Hardwired PWM Response to Internal Temperature Faults External Temperature Faults Timing Faults External Faults Higher-Level Fault Handling Status Registers and ALERT Masking FAULT Pin I/O Fault Log Operation Fault Log Details Factory Default Operation Serial Interface Serial Bus Addressing Serial Bus Timeout Serial Communication Errors PMBus Command Summary PMBus Commands Data Formats Applications Information Efficiency Considerations Power Stage Selection and Interface Using The VDR Monitor Unused TSNS Inputs PWM Frequency and Inductor Selection CIN Selection COUT Selection Programmable Loop Compensation PCB Layout Considerations Output Voltage Sensing Classical Analog Output Voltage Control PMBus Output Voltage Control Using Output Voltage Servo Soft-Start and Stop Time-Based Output Sequencing and Ramping Voltage-Based Output Sequencing PWM Frequency Synchronization PolyPhase Operation and Load Sharing Resistor Configuration Pins Internal Regulator Outputs IC Junction Temperature Derating EEPROM Retention at Temperature Configuring Open-Drain Pins PMBus Communication and Command Processing Status and Fault Log Management LTpowerPlay – An Interactive Digital Power GUI Interfacing to the DC1613 Design Example PMBus Command Details Addressing and Write Protect PAGE PAGE_PLUS_WRITE PAGE_PLUS_READ WRITE_PROTECT MFR_ADDRESS MFR_RAIL_ADDRESS General Device Configuration PMBUS_REVISION CAPABILITY MFR_CONFIG_ALL On, Off and Margin Control ON_OFF_CONFIG OPERATION MFR_RESET PWM Configuration FREQUENCY_SWITCH MFR_CHAN_CONFIG MFR_PWM_CONFIG_LTC3888-1 MFR_PWM_MODE_LTC3888-1 MFR_PWM_COMP Input Voltage and Limits VIN_ON VIN_OFF VIN_OV_FAULT_LIMIT VIN_UV_WARN_LIMIT Output Voltage and Limits VOUT_MODE VOUT_COMMAND VOUT_MAX MFR_VOUT_MAX VOUT_MARGIN_HIGH VOUT_MARGIN_LOW VOUT_SCALE_LOOP VOUT_OV_FAULT_LIMIT VOUT_OV_WARN_LIMIT VOUT_UV_WARN_LIMIT VOUT_UV_FAULT_LIMIT Output Current and Limits IOUT_CAL_GAIN MFR_LOAD_EMULATION MFR_LOAD_EMULATION IOUT_OC_FAULT_LIMIT IOUT_OC_WARN_LIMIT Output Timing, Delays, and Ramping MFR_RESTART_DELAY TON_DELAY TON_MAX_FAULT_LIMIT VOUT_TRANSITION_RATE TOFF_DELAY TOFF_MAX_WARN_LIMIT External Temperature and Limits MFR_TEMP_1_GAIN MFR_TEMP_1_OFFSET OT_FAULT_LIMIT OT_WARN_LIMIT Status Reporting STATUS_BYTE STATUS_WORD STATUS_VOUT STATUS_IOUT STATUS_INPUT STATUS_TEMPERATURE STATUS_CML STATUS_MFR_SPECIFIC MFR_PADS_LTC3888-1 MFR_COMMON MFR_INFO CLEAR_FAULTS Telemetry READ_VIN MFR_VIN_PEAK READ_VOUT MFR_VOUT_PEAK READ_IOUT MFR_IOUT_PEAK MFR_TOTAL_IOUT MFR_READ_ALL_IOUT READ_TEMPERATURE_1 MFR_TEMPERATURE_1_PEAK READ_TEMPERATURE_2 MFR_TEMPERATURE_2_PEAK READ_FREQUENCY MFR_CLEAR_PEAKS Fault Response and Communication VIN_OV_FAULT_RESPONSE VOUT_OV_FAULT_RESPONSE VOUT_UV_FAULT_RESPONSE IOUT_OC_FAULT_RESPONSE OT_FAULT_RESPONSE MFR_OT_FAULT_RESPONSE TON_MAX_FAULT_RESPONSE MFR_RETRY_DELAY SMBALERT_MASK MFR_FAULT_PROPAGATE MFR_FAULT_RESPONSE MFR_FAULT_LOG MFR_FAULT_LOG_CLEAR EEPROM User Access STORE_USER_ALL RESTORE_USER_ALL MFR_COMPARE_USER_ALL MFR_FAULT_LOG_STORE MFR_EE_xxxx USER_DATA_0x Unit Identification MFR_ID IC_DEVICE_ID MFR_SPECIAL_ID Package Description Typical Applications Related Parts