LTC2977 8-Channel PMBus Power System Manager Featuring Accurate Output Voltage Measurement FEATURES DESCRIPTION n Sequence, Trim, Margin and Supervise Eight Power The LTC 2977 is an 8-channel Power System Manager used to sequence, trim (servo), margin, supervise, Supplies n manage faults, provide telemetry and create fault logs. Manage Faults, Monitor Telemetry and Create Fault Logs n PMBus commands support power supply sequencing, PMBus Compliant Command Set n precision point-of-load voltage adjustment and margi- Supported by LTpowerPlay GUI n ning. DACs use a proprietary soft-connect algorithm to Margin or Trim Supplies to Within 0.25% of Target n minimize supply disturbances. Supervisory functions Fast OV/UV Supervisors Per Channel n include overvoltage and undervoltage threshold limits Coordinate Sequencing and Fault Management for eight power supply output channels and one power Across Multiple LTC PSM Devices supply input channel, as well as over and under tempera- n Automatic Fault Logging to Internal EEPROM ture limits. Programmable fault responses can disable the n Operate Autonomously without Additional Software power supplies with optional retry after a fault is detected. n Internal Temperature and Input Voltage Supervisors Faults that disable a power supply can automatically trig- n Accurate Monitoring of Eight Output Voltages, Input ger black box EEPROM storage of fault status and asso- Voltage and Internal Die Temperature 2 ciated telemetry. An internal 16-bit ADC monitors eight n I C/SMBus Serial Interface output voltages, one input voltage, and die temperature. n Can Be Powered from 3.3V, or 4.5V to 15V In addition, odd numbered channels can be configured n Programmable Watchdog Timer to measure the voltage across a current sense resistor. A n 100% Pin-Compatible Upgrade to the LTC2978/LTC2978A programmable watchdog timer monitors microprocessor n Available in 64-Pin 9mm 9mm QFN Package activity for a stalled condition and resets the microproces- n AEC-Q100 Qualified for Automotive Applications sor if necessary. A single wire bus synchronizes power supplies across multiple LTC Power System Management APPLICATIONS (PSM) devices. Configuration EEPROM with ECC sup- n Computers and Network Servers ports autonomous operation without additional software. n Industrial Test and Measurement n High Reliability Systems All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 7382303, 7420359 and 7940091. n Medical Imaging n Video TYPICAL APPLICATION 8-Channel PMBus Power System Manager Typical ADC Total Unadjusted Error vs Temperature IBC 4.5V V 15V IBUS DC IN OUT IN 0.25 EN V = 1.8V SENSEP0 V IN SNS V IN 0.20 THREE TYPICAL PARTS V OUT V IN EN 0.15 DC/DC + * LTC2977 MAY ALSO BE 0.10 V * CONVERTER PWR POWERED DIRECTLY FROM V * V LOAD V RUN 0.05 AN EXTERNAL 3.3V SUPPLY SENSE FB DD33 0 LTC2977 R20 0.05 SDA V 0.10 PMBus DAC SCL R30 INTERFACE R10 0.15 ALERTB 0.20 CONTROL V OUT EN FAULT 0.25 50 10 30 50 70 90 110 30 10 NOTE: SOME DETAILS OMITTED FOR CLARITY PWRGD TEMPERATURE (C) ONLY ONE OF EIGHT CHANNELS SHOWN 2977 TA01b 2977 TA01a Rev. E 1 Document Feedback For more information www.analog.com ERROR (%)LTC2977 TABLE OF CONTENTS Features ..........................................................1 Output Voltage Related Commands ............................. 36 Applications .....................................................1 VOUT COMMAND, VOUT MAX, VOUT MARGIN Typical Application .............................................1 HIGH, VOUT MARGIN LOW, VOUT OV FAULT Description ......................................................1 LIMIT, VOUT OV WARN LIMIT, VOUT UV WARN Absolute Maximum Ratings ..................................4 LIMIT, VOUT UV FAULT LIMIT, POWER GOOD ON Order Information ..............................................4 and POWER GOOD OFF ........................................ 36 Pin Configuration ...............................................4 Input Voltage Related Commands ............................... 36 Electrical Characteristics ......................................5 VIN ON, VIN OFF, VIN OV FAULT LIMIT, VIN OV PMBus Timing Diagram .......................................9 WARN LIMIT, VIN UV WARN LIMIT and VIN UV Typical Performance Characteristics ...................... 10 FAULT LIMIT ........................................................... 36 Pin Functions .................................................. 13 Temperature Related Commands ................................ 37 Block Diagram ................................................ 15 OT FAULT LIMIT, OT WARN LIMIT, UT WARN Operation ...................................................... 16 LIMIT and UT FAULT LIMIT ................................... 37 Operation Overview .......................................................16 Timer Limits ................................................................. 37 EEPROM ....................................................................17 TON DELAY, TON RISE, TON MAX FAULT LIMIT Reset ..............................................................................17 and TOFF DELAY ..................................................... 37 Other Operations ...........................................................17 Fault Response for Voltages Measured by the High Clock Sharing ............................................................17 Speed Supervisor ......................................................... 38 PMBus Serial Digital Interface ......................................18 VOUT OV FAULT RESPONSE and VOUT UV PMBus....................................................................... 18 FAULT RESPONSE .................................................. 38 Device Address ........................................................ 21 Fault Response for Values Measured by the ADC ....... 39 Processing Commands ........................................... 22 OT FAULT RESPONSE, UT FAULT RESPONSE, PMBus Command Summary ............................... 23 VIN OV FAULT RESPONSE and VIN UV FAULT Summary Table ........................................................ 23 RESPONSE ............................................................... 39 Data Formats ........................................................... 27 Timed Fault Response .................................................. 40 PMBus Command Description ............................. 28 TON MAX FAULT RESPONSE .............................. 40 Addressing and Write Protect ...................................... 28 Status Commands .........................................................41 PAGE ........................................................................ 28 STATUS BYTE ..........................................................41 WRITE PROTECT .................................................... 28 STATUS WORD ........................................................41 WRITE PROTECT Pin ............................................... 29 STATUS VOUT......................................................... 42 MFR PAGE FF MASK ............................................ 29 STATUS INPUT ....................................................... 42 MFR I2C BASE ADDRESS ................................... 30 STATUS TEMPERATURE ........................................ 42 MFR COMMAND PLUS, MFR DATA PLUS0, STATUS CML .......................................................... 43 MFR DATA PLUS1, MFR STATUS PLUS0, and STATUS MFR SPECIFIC ........................................ 43 MFR STATUS PLUS1 ............................................ 30 ADC Monitoring Commands ........................................ 44 Reading Fault Log Using Command Plus and Mfr READ VIN ................................................................ 44 data plus0 ............................................................... 31 READ VOUT ............................................................ 44 Peek Operation using Mfr data plus0 ................... 32 READ TEMPERATURE 1 ........................................ 44 Enabling and Disabling Poke Operations ................ 32 PMBUS REVISION .................................................. 44 Poke Operation Using Mfr data plus0 ................... 32 Manufacturer Specific Commands .............................. 45 Command Plus Operations Using Mfr data plus1 32 MFR CONFIG LTC2977.......................................... 45 Operation, Mode and EEPROM Commands ................ 33 Tracking Supplies On and Off .................................. 46 OPERATION ............................................................. 33 Tracking Implementation ......................................... 48 ON OFF CONFIG ..................................................... 34 MFR CONFIG ALL LTC2977................................. 49 CLEAR FAULTS ....................................................... 34 MFR FAULTBz0 PROPAGATE, MFR FAULTBz1 STORE USER ALL and RESTORE USER ALL .... 35 PROPAGATE............................................................. 50 CAPABILITY ............................................................. 35 MFR PWRGD EN ....................................................51 VOUT MODE ........................................................... 35 Rev. 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