LTC2974 4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement FEATURES DESCRIPTION n Sequence, Trim, Margin and Supervise Four Power The LTC 2974 is a 4-channel Power System Manager used Supplies to sequence, trim (servo), margin, supervise, manage n Manage Faults, Monitor Telemetry and Create Fault Logs faults, provide telemetry and create fault logs. PMBus n PMBus Compliant Command Set commands support power supply sequencing, precision n Supported by LTpowerPlay GUI point-of-load voltage adjustment and margining. DACs n Margin or Trim Supplies to within 0.25% of Target use a proprietary soft-connect algorithm to minimize n Fast OV/UV Supervisors Per Channel supply disturbances. Supervisory functions include over n Fast Output Current Supervisors Per Channel and under current, voltage and temperature threshold n Coordinate Sequencing and Fault Management limits for four power supply output channels as well as Across Multiple LTC PSM Devices over and under voltage threshold limits for a single power n Automatic Fault Logging to Internal EEPROM supply input channel. Programmable fault responses n Operate Autonomously without Additional Software can disable the power supplies with optional retry after a n External Temperature and Input Voltage Supervisors fault is detected. Faults that disable a power supply can n Accurate Monitoring of Four Output Voltages, Four automatically trigger black box EEPROM storage of fault Output Currents, Four External Temperatures, Input status and associated telemetry. An internal 16-bit ADC Voltage and Internal Die Temperature monitors four output voltages, four output currents, four 2 n I C/SMBus Serial Interface - external temperatures, one input voltage and die tempera n Can Be Powered from 3.3V, or 4.5V to 15V ture. Output power is also calculated. A programmable n Available in 64-Lead 9mm 9mm QFN Package watchdog timer monitors microprocessor activity for a stalled condition and resets the microprocessor if neces- sary. A single wire bus synchronizes power supplies across APPLICATIONS multiple LTC Power System Management (PSM) devices. n Computers and Network Servers Configuration EEPROM with ECC supports autonomous n Industrial Test and Measurement operation without additional software. n High Reliability Systems All registered trademarks and trademarks are the property of their respective owners. Protected n Medical Imaging by U.S. patents, including 7382303, 7420359 and 7940091. n Video TYPICAL APPLICATION 4-Channel PMBus Power System Manager ADC Total Unadjusted Error IBC vs Temperature 4.5V V 15V IBUS DC IN OUT IN 0.07 EN V I IN SENSEP 0.06 V V OUT IN SNS DC/DC 0.05 AUXFAULTB CONVERTER 0.04 * LTC2974 MAY ALSO BE V RUN V * I FB PWR SENSEM POWERED DIRECTLY FROM 0.03 AN EXTERNAL 3.3V SUPPLY V * V DD33 SENSEP 0.02 LTC2974 LOAD 0.01 V R20 SENSEM SDA 0 PMBus V DAC SCL 0.01 INTERFACE R30 R10 ALERTB 0.02 CONTROL THREE TYPICAL PARTS V 0.03 OUT EN FAULT 50 25 0 25 50 75 100 T SENSE PWRGD MMBT3906 TEMPERATURE (C) 2974 TA01b NOTE: SOME DETAILS OMITTED FOR CLARITY ONLY ONE OF FOUR CHANNELS SHOWN Rev. 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........................................................4 LIMIT, VIN UV WARN LIMIT and Electrical Characteristics ...............................................5 VIN UV FAULT LIMIT .......................................................47 PMBus Timing Diagram .................................................9 Output Voltage Commands and Limits ....................................48 Typical Performance Characteristics ............................... 10 VOUT MODE ......................................................................48 Pin Functions ........................................................... 14 VOUT COMMAND, VOUT MAX, VOUT MARGIN HIGH, Block Diagram .......................................................... 16 VOUT MARGIN LOW, VOUT OV FAULT LIMIT, VOUT OV Operation................................................................ 17 WARN LIMIT, VOUT UV WARN LIMIT, VOUT UV FAULT LTC2974 Operation Overview ..................................................17 LIMIT, POWER GOOD ON and POWER GOOD OFF ........49 EEPROM .............................................................................18 MFR VOUT DISCHARGE THRESHOLD ............................49 AUXFAULTB .............................................................................18 MFR DAC ...........................................................................49 RESETB ...................................................................................19 Output Current Commands and Limits ....................................50 PMBus Serial Digital Interface ................................................19 IOUT CAL GAIN ................................................................50 PMBus ................................................................................19 IOUT OC FAULT LIMIT, IOUT OC WARN LIMIT and Device Address ...................................................................19 IOUT UC FAULT LIMIT .....................................................51 Processing Commands ......................................................20 MFR IOUT CAL GAIN TC ................................................51 PMBUS Command Summary ......................................... 23 External Temperature Commands And Limits .........................52 Summary Table ..................................................................23 OT FAULT LIMIT, OT WARN LIMIT, UT WARN LIMIT and Data Formats ......................................................................28 UT FAULT LIMIT ...............................................................52 PMBus Command Description ....................................... 29 MFR TEMP 1 GAIN and MFR TEMP 1 OFFSET ..............52 Addressing and Write Protect .................................................29 MFR T SELF HEAT, MFR IOUT CAL GAIN TAU INV and PAGE ...................................................................................29 MFR IOUT CAL GAIN THETA ..........................................53 WRITE PROTECT ............................................................... 30 Sequencing Timing Limits and Clock Sharing .........................55 Write Protect Pin ................................................................30 TON DELAY, TON RISE, TON MAX FAULT LIMIT and MFR PAGE FF MASK .......................................................30 TOFF DELAY ......................................................................55 MFR I2C BASE ADDRESS ...............................................31 MFR RESTART DELAY .....................................................55 MFR COMMAND PLUS ....................................................31 Watchdog Timer and Power Good ...........................................56 MFR DATA PLUS0 and MFR DATA PLUS1 ....................31 MFR PWRGD EN ..............................................................56 MFR STATUS PLUS0, and MFR STATUS PLUS1 ...........31 Clock Sharing .....................................................................56 Reading Fault Log Using Command Plus and MFR POWERGOOD ASSERTION DELAY.........................57 Mfr data plus0 ..................................................................32 Watchdog Operation ...........................................................57 Peek Operation Using Mfr data plus0 ..............................33 MFR WATCHDOG T FIRST and MFR WATCHDOG T ......57 Enabling and Disabling Poke Operations ............................33 Fault Responses ......................................................................58 Poke Operation Using Mfr data plus0 ..............................33 Clearing Latched Faults ......................................................58 Command Plus Operations Using Mfr data plus1 ............33 VOUT OV FAULT RESPONSE and VOUT UV FAULT On/Off Control, Margining and Configuration .........................34 RESPONSE .........................................................................59 OPERATION ........................................................................34 IOUT OC FAULT RESPONSE and IOUT UC FAULT ON OFF CONFIG ................................................................35 RESPONSE .........................................................................60 MFR CONFIG LTC2974 .....................................................36 OT FAULT RESPONSE, UT FAULT RESPONSE, VIN OV Cascade Sequence ON with Time-Based Sequence OFF ....37 FAULT RESPONSE and VIN UV FAULT RESPONSE ........61 MFR CONFIG2 LTC2974 ...................................................39 TON MAX FAULT RESPONSE ..........................................62 MFR CONFIG3 LTC2974 ...................................................39 MFR RETRY DELAY ..........................................................62 Tracking Supplies On and Off .............................................41 MFR RETRY COUNT .........................................................62 Tracking Implementation ....................................................42 Shared External Faults ............................................................63 MFR CONFIG ALL LTC2974 ............................................43 MFR FAULTB0 PROPAGATE and MFR FAULTB1 Programming User EEPROM Space ........................................44 PROPAGATE .......................................................................63 STORE USER ALL and RESTORE USER ALL ................45 MFR FAULTB0 RESPONSE and MFR FAULTB1 Bulk Programming the User EEPROM Space .....................45 RESPONSE .........................................................................64 MFR EE UNLOCK ..............................................................45 Fault Warning and Status ........................................................65 Rev. 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