Datasheet LTM4678 (Analog Devices) - 3

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TABLE OF CONTENTS Applications Information ..50
General Configuration Commands ..78 VIN to VOUT Step-Down Ratios ...50 On/Off/Margin ...79 Input Capacitors ..50 PWM Configuration ..81 Output Capacitors ..50 Voltage ..84 Light Load Current Operation ...50 Input Voltage and Limits ...84 Switching Frequency and Phase .. 51 Output Voltage and Limits ..85 Recommended Switching Frequency for Various Output Current and Limits ..88 VIN-to-VOUT Step-Down Scenarios ...52 Input Current and Limits ..90 Output Current Limit Programming ...52 Temperature ..91 Minimum On-Time Considerations ...53 Power Stage DCR Temperature Calibration ...91 Variable Delay Time, Soft-Start and Output Timing ...92 Voltage Ramping ...53 Timing—On Sequence/Ramp ...92 Digital Servo Mode ..53 Timing—Off Sequence/Ramp ..93 Soft Off (Sequenced Off) ...54 Precondition for Restart ...94 Undervoltage Lockout ..55 Fault Response ...94 Fault Detection and Handling ...55 Fault Responses Al Faults ..94 Open-Drain Pins ...55 Fault Responses Input Voltage..95 Phase-Locked Loop and Frequency Fault Responses Output Voltage ...95 Synchronization ...56 VOUT_OV_FAULT_RESPONSE Data Byte Contents .. 96 Input Current Sense Amplifier ..57 VOUT_UV_FAULT_RESPONSE Data Byte Contents ...97 Programmable Loop Compensation ..57 Fault Responses Output Current ...98 Checking Transient Response ..58 OUT_OC_FAULT_RESPONSE Data Byte Contents ...99 PolyPhase Configuration ...59 Fault Responses IC Temperature ..99 Connecting The USB to I2C/SMBus/PMBus Data Byte Contents MFR_OT_FAULT_RESPONSE ...100 Control er to the LTM4678 In System ..59 Fault Responses External Temperature ... 100 LTpowerPlay: An Interactive GUI for Digital Power ... 60 Fault Sharing ... 101 PMBus Communication and Command Processing ... 60 Thermal Considerations and Output Current Derating .. 62 Fault Sharing Propagation .. 101 Table 10 thru Table 11: Output Current Derating..65 FAULTn Propagate Fault Configuration .. 102 0.9V Output ..65 Fault Sharing Response .. 103 1.8V Output ...65 Scratchpad .. 103 Channel Output Voltage vs Component Selection, Identification ... 104 0A to 12.5A/μs Load Step Output Capacitor- Fault Warning and Status .. 105 GRM32ER60G337ME05L, 330μF, 4V, X5R, Murata .. 66 Telemetry ...111 Channel Output Voltage vs Component Selection, NVM Memory Commands .. 115 0A to 12.5A/μs Load Step ...67 Store/Restore ... 115 Dual Phase Single Output – Ceramic and Poscap Fault Logging .. 116 Output Capacitors ...67 Fault Logging .. 117
Applications Information-Derating Curves ..68
Explanation of Position_Fault Values .. 119 EMI Performance ...69 Block Memory Write/Read .. 120 Safety Considerations ..69
Package Description ... 121
Layout Checklist/Example ..69 LTM4678 BGA Pinout ... 121
Typical Applications ..71 Revision History .. 123 PMBus Command Details ...76 Package Photograph ... 124
Addressing and Write Protect ...76
Design Resources .. 124 Related Parts .. 124
Rev. A For more information www.analog.com 3 Document Outline Features Applications Typical Application Description Table of Contents 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 Overview, Major Features EEPROM with ECC Power-Up and Initialization Soft-Start Time-Based Sequencing Voltage-Based Sequencing Shutdown Light-Load Current Operation Switching Frequency and Phase PWM Loop Compensation Output Voltage Sensing INTVCC/EXTVCC Power Output Current Sensing and Sub Milliohm DCR Current Sensing Input Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins VOUTn _CFG Pin Strapping Look-Up Table for the LTM4678’s Output Voltage, Coarse Setting (Not Applicable if MFR_CONFIG_ALL[6] = 1b) VTRIMn_CFG Pin Strapping Look-Up Table for the LTM4678’s Output Voltage, Fine Adjustment Setting (Not Applicable if MFR_CONFIG_ALL[6] = 1b) FSWPH_CFG Pin Strapping Look-Up Table to Set the LTM4678’s Switching Frequency and Channel Phase-Interleaving Angle (Not Applicable if MFR_CONFIG_ALL[6] = 1b) ASEL Pin Strapping Look-Up Table to Set the LTM4678’s Slave Address (Applicable Regardless of MFR_CONFIG_ALL[6] Setting) LTM4678 MFR_ADDRESS Command Examples Expressed in 7- and 8-Bit Addressing Fault Detection and 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 IIN/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 Response External Overtemperature and Undertemperature Fault Response Responses to Input Overcurrent and Output Undercurrent Faults Responses to External Faults Fault Logging Bus Timeout Protection Similarity Between PMBus, SMBus and I2C 2-Wire Interface PMBus Serial Digital Interface Abbreviations of Supported Data Formats Figure 7 to Figure 24 PMBus Protocols PMBus Command Summary PMBus Commands PMBus Commands Summary (Note: The Data Format Abbreviations are Detailed in Table 8) Data Format Abbreviations Applications Information VIN to VOUT Step-Down Ratios Input Capacitors Output Capacitors Light Load Current Operation Switching Frequency and Phase Recommended Switching Frequency for Various VIN-to-VOUT Step-Down Scenarios Output Current Limit Programming 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 Input Current Sense Amplifier Programmable Loop Compensation Checking Transient Response PolyPhase Configuration Connecting The USB to I2C/SMBus/PMBus Controller to the LTM4678 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing Thermal Considerations and Output Current Derating Table 10 thru Table 11: Output Current Derating 0.9V Output 1.8V Output Channel Output Voltage vs Component Selection, 0A to 12.5A/μs Load Step Output Capacitor-GRM32ER60G337ME05L, 330μF, 4V, X5R, Murata Low VOUT Range for VOUT ≤ 2.5V High VOUT Range for 2.5V ≤ VOUT ILIMIT Range = High Channel Output Voltage vs Component Selection, 0A to 12.5A/μs Load Step Low VOUT Range for VOUT ≤ 2.5V High VOUT Range for 2.5V ≤ VOUT ILIMIT Range = High Dual Phase Single Output – Ceramic and Poscap Output Capacitors Applications Information-Derating Curves EMI Performance Safety Considerations Layout Checklist/Example Typical Applications 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 Power Stage DCR 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 VOUT_OV_FAULT_RESPONSE Data Byte Contents VOUT_UV_FAULT_RESPONSE Data Byte Contents Fault Responses Output Current OUT_OC_FAULT_RESPONSE Data Byte Contents Fault Responses IC Temperature Data Byte Contents MFR_OT_FAULT_RESPONSE Fault Responses External Temperature Fault Sharing Fault Sharing Propagation FAULTn Propagate Fault Configuration Fault Sharing Response Scratchpad Identification Fault Warning and Status Telemetry NVM Memory Commands Store/Restore Fault Logging Fault Logging Explanation of Position_Fault Values Block Memory Write/Read Package Description LTM4678 BGA Pinout Revision History Package Photograph Design Resources Related Parts