link to page 1 link to page 1 link to page 1 link to page 1 link to page 3 link to page 3 link to page 3 link to page 4 link to page 11 link to page 14 link to page 19 link to page 19 link to page 20 link to page 21 link to page 22 link to page 22 link to page 24 link to page 26 link to page 30 link to page 33 link to page 34 link to page 35 link to page 35 link to page 36 link to page 37 link to page 38 link to page 38 link to page 38 link to page 38 link to page 39 link to page 40 link to page 40 link to page 51 link to page 51 link to page 51 link to page 51 link to page 52 link to page 54 link to page 54 link to page 54 link to page 55 link to page 56 link to page 56 link to page 57 link to page 57 link to page 58 link to page 59 link to page 59 link to page 59 link to page 59 link to page 59 link to page 63 link to page 63 link to page 64 link to page 65 link to page 73 link to page 74 link to page 74 link to page 75 link to page 81 link to page 81 link to page 81 link to page 82 link to page 82 link to page 86 link to page 86 link to page 88 link to page 89 link to page 91 link to page 93 link to page 96 link to page 99 link to page 100 link to page 102 link to page 110 link to page 112 link to page 112 link to page 114 link to page 121 link to page 125 link to page 132 link to page 133 link to page 134 link to page 135 link to page 136 link to page 136 link to page 136 LTM4676A Table oF conTenTs Features ... 1 Open-Drain Pins ...57 Applications .. 1 Phase-Locked Loop and Frequency Synchronization...58 Typical Application .. 1 RCONFIG Pin-Straps (External Resistor Description.. 1 Configuration Pins) ..59 Absolute Maximum Ratings .. 3 Voltage Selection ...59 Order Information .. 3 Connecting the USB to the I2C/SMBus/PMBus Pin Configuration .. 3 Control er to the LTM4676A In System ..59 Electrical Characteristics ... 4 LTpowerPlay: An Interactive GUI for Digital Power Typical Performance Characteristics .. 11 System Management ...63 Pin Functions .. 14 PMBus Communication and Command Processing ...64 Simplified Block Diagram ... 19 Thermal Considerations and Output Current Derating ...65 Decoupling Requirements ... 19 EMI Performance ...73 Functional Diagram .. 20 Safety Considerations .. 74 Test Circuits ... 21 Layout Checklist/Example .. 74 Operation... 22Typical Applications .. 75 Power Module Introduction ..22 Appendix A ... 81 Power Module Configurability and Readback Data .. 24 Similarity Between PMBus, SMBus and I2C Time-Averaged and Peak Readback Data ...26 2-Wire Interface ...81 Power Module Overview ..30 Appendix B ... 82 EEPROM ...33 PMBus Serial Digital Interface ...82 Serial Interface ...34 Appendix C: PMBus Command Details .. 86 Device Addressing ...35 Addressing and Write Protect ..86 Fault Detection and Handling ...35 General Configuration Registers ..88 Responses to VOUT and IOUT Faults..36 On/Off/Margin ..89 Responses to Timing Faults ...37 PWM Config ...91 Responses to SVIN OV Faults ...38 Voltage ...93 Responses to OT/UT Faults ..38 Current ...96 Responses to External Faults ..38 Temperature ...99 Fault Logging ...38 Timing .. 100 Bus Timeout Protection ...39 Fault Response ... 102 PMBus Command Summary .. 40 Fault Sharing .. 110 PMBus Commands ...40 Scratchpad ... 112 VIN to VOUT Step-Down Ratios ... 51 Identification .. 112 Input Capacitors ... 51 Fault Warning and Status ... 114 Output Capacitors .. 51 Telemetry ... 121 Light Load Current Operation ... 51 NVM (EEPROM) Memory Commands .. 125 Switching Frequency and Phase ..52 Package Description ... 132 Minimum On-Time Considerations ...54 Package Photograph ... 133 Variable Delay Time, Soft-Start and Output Voltage Package Description ... 134 Ramping ...54 Revision History .. 135 Digital Servo Mode ..55 Typical Application ... 136 Soft Off (Sequenced Off) ...56 Design Resources .. 136 Undervoltage Lockout ..56 Related Parts .. 136 Fault Detection and Handling ...57 4676afa 2 For more information www.linear.com/LTM4676A Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Simplified Block Diagram Decoupling Requirements Functional Diagram Test Circuits Operation Power Module Introduction Power Module Configurability and Readback Data Time-Averaged and Peak Readback Data Power Module Overview EEPROM Serial Interface Device Addressing Fault Detection and Handling Responses to VOUT and IOUT Faults Responses to Timing Faults Responses to SVIN OV Faults Responses to OT/UT Faults Responses to External Faults Fault Logging Bus Timeout Protection PMBus Command Summary PMBus Commands VIN to VOUT Step-Down Ratios Input Capacitors Output Capacitors Light Load Current Operation Switching Frequency and Phase Minimum On-Time Considerations Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) Undervoltage Lockout Fault Detection and Handling Open-Drain Pins Phase-Locked Loop and Frequency Synchronization RCONFIG Pin-Straps (External Resistor Configuration Pins) Voltage Selection Connecting the USB to the I2C/SMBus/PMBus Controller to the LTM4676A In System LTpowerPlay: An Interactive GUI for Digital Power System Management PMBus Communication and Command Processing Thermal Considerations and Output Current Derating EMI Performance Safety Considerations Layout Checklist/Example Typical Applications Appendix A Similarity Between PMBus, SMBus and I2C 2-Wire Interface Appendix B PMBus Serial Digital Interface Appendix C: PMBus Command Details Addressing and Write Protect General Configuration Registers On/Off/Margin PWM Config Voltage Current Temperature Timing Fault Response Fault Sharing Scratchpad Identification Fault Warning and Status Telemetry NVM (EEPROM) Memory Commands Package Description Package Photograph Package Description Revision History Typical Application Design Resources Related Parts