Datasheet LTM4664 (Analog Devices) - 121

LTM4664
PMBus COMMAND DETAILS STATUS_BYTE Message Contents: BIT STATUS BIT NAME MEANING
7* BUSY A fault was declared because the LTM4664 was unable to respond. 6 OFF This bit is set if the channel is not providing power to its output, regardless of the reason, including simply not being enabled. 5 VOUT_OV An output overvoltage fault has occurred. 4 IOUT_OC An output overcurrent fault has occurred. 3 VIN_UV Not supported (LTM4664 returns 0). 2 TEMPERATURE A temperature fault or warning has occurred. 1 CML A communications, memory or logic fault has occurred. 0* NONE OF THE ABOVE A fault Not listed in bits[7:1] has occurred. *ALERT can be asserted if either of these bits is set. They may be cleared by writing a 1 to their bit position in the STATUS_BYTE, in lieu of a CLEAR_ FAULTS command. This command has one data byte.
STATUS_WORD
The STATUS_WORD command returns a two-byte summary of the channel's fault condition. The low byte of the STATUS_WORD is the same as the STATUS_BYTE command.
STATUS_WORD High Byte Message Contents: BIT STATUS BIT NAME MEANING
15 VOUT An output voltage fault or warning has occurred. 14 IOUT An output current fault or warning has occurred. 13 INPUT An input voltage fault or warning has occurred. 12 MFR_SPECIFIC A fault or warning specific to the LTM4664 has occurred. 11 POWER_GOOD# The POWER_GOOD state is false if this bit is set. 10 FANS Not supported (LTM4664 returns 0). 9 OTHER Not supported (LTM4664 returns 0). 8 UNKNOWN Not supported (LTM4664 returns 0). If any of the bits in the upper byte are set, NONE_OF_THE_ABOVE is asserted. This command has two data bytes.
STATUS_VOUT
The STATUS_VOUT command returns one byte of VOUT status information.
STATUS_VOUT Message Contents: BIT MEANING
7 VOUT overvoltage fault. 6 VOUT overvoltage warning. 5 VOUT undervoltage warning. 4 VOUT undervoltage fault. 3 VOUT max warning. 2 TON max fault. 1 TOFF max fault. 0 Not supported (LTM4664 returns 0). Rev. 0 For more information www.analog.com 121 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics 4:1 Divider Block Diagram Dual 25A Power System Management (PSM) Block Diagram 4:1 Divider Operation 4:1 Divider Description Main Control INTVCCS1,2/EXTVCCS1,2 Power Start-Up and Shutdown Fault Protection and Thermal Shutdown High Side Current Sensing Frequency Selection Power Good and UV (PGOODSn and UVSn pins) Additional Overvoltage Protection 4:1 Divider Application Information Voltage Divider Pre-Balance Before Switching Overcurrent Protection Window Comparator Programming Effective Open Loop Output Resistance and Load Regulation Undervoltage Lockout Fault Response and Timer Programming Design Example Dual 25A PSM Operation PSM Section 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 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 Figure 11 thru Figure 28 PMBus Protocols PMBus Command Summary PMBus Commands Dual 25A PSM Applications Information VIN to VOUT Step-Down Ratios Input Capacitors Output Capacitors Light Load Current Operation Switching Frequency and Phase 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 LTM4664 In-System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing Thermal Considerations and Output Current Derating Table 10 and Table 11: Output Current Derating (Based on Demo Board) Dual 25A PSM 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 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 NVM Memory Commands Store/Restore Fault Logging Block Memory Write/Read Package Description Typical Applications Related Parts