Datasheet LTC2972 (Analog Devices)

LTC2972 2-Channel PMBus Power System Manager Featuring Programmable Power Good Outputs
FEATURES DESCRIPTION
n
Sequence, Trim, Margin and Supervise Two
The LTC®2972 is a 2-channel Power System Manager
Power Supplies
used to sequence, trim (servo), margin, supervise, man- n
Manage Faults, Monitor Telemetry
age 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 sup- n
Monitor Input Current (±1%) and Accumulate Energy
ply disturbances. Supervisory functions include over and n
Fast OV/UV Supervisors per Channel
under voltage and temperature threshold limits for two n
Coordinate Sequencing and Fault Management
power supply output channels as well as over and under
Across Multiple ADI PSM Devices
voltage threshold limits for a single power supply input n
Automatic Fault Logging to Internal EEPROM
channel. Programmable fault responses can disable the n
Operate Autonomously Without Additional Software
power supplies with optional retry after a fault is detected. n
Configurable Power Good Output Pins
Faults that disable a power supply can automatically trigger n Accurate Monitoring of Output Voltage, Output black box EEPROM storage of fault status and associated Current, Temperature, and Input Voltage and Current telemetry. An internal 16-bit ADC monitors two output volt- n 1.8V to 3.3V I2C/SMBus Serial Interface ages, two output currents, two external temperatures, input n Connect Directly to Regulator IMON Pins voltage and current, and die temperature. Input power, n Can Be Powered from 3.3V, or 4.5V to 15V energy, and output power are also calculated. A program- n Available in 44-Pin 6mm × 7mm QFN Package mable 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 ADI 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 by U.S. Patents including 7382303, 7420359, 8648623 and 8920026. Video and Medical Imaging
TYPICAL APPLICATION Closed-Loop Servo Error vs Temperature
IBC 4.5V ≤ VIBUS ≤ 15V DC 0.25 IN IN OUT 80 PARTS SOLDERED DOWN * 0.20 V R ALERTB IN = 1.0V CONTROL SCL PMBus 0.15 V IN_SNS V PW INTERFACE I IN_SNSP I IN_SNSM FAULT SDA 0.10 VDD33* PWRGD VDDIO 0.05 ISENSEP0 ISENSEP1 V V IN RSNS ISENSEM0 ISENSEM1 R IN SNS 0.00 VOUT VOUT VSENSEP0 LTC2972 VSENSEP1 –0.05 DC/DC DC/DC R20 CONVERTER R20 LOAD LOAD CONVERTER –0.10 V RUN V SENSEM0 VSENSEM1 VFB RUN ERROR (% OF READING) FB –0.15 R10 R10 R30 R30 VDAC0 VDAC1 –0.20 VOUT_EN0 VOUT_EN1 PG0 PG1 –0.25 T –50 –25 0 25 50 75 100 SENSE0 T *LTC2972 MAY ALSO BE SENSE1 NOTE: SOME DETAILS POWERED DIRECTLY FROM OMITTED FOR CLARITY 2972 TA01a TEMPERATURE (°C) AN EXTERNAL 3.3V SUPPLY 2972 TA01b Rev. C Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics PMBus Timing Diagram Typical Performance Characteristics Pin Functions Block Diagram Operation LTC2972 Operation Overview EEPROM AUXFAULTB RESETB VDDIO PMBus Serial Digital Interface PMBus Device Address Processing Commands Addressing and Write Protect PAGE WRITE_PROTECT WRITE PROTECT Pin MFR_PAGE_FF_MASK MFR_I2C_BASE_ADDRESS MFR_COMMAND_PLUS MFR_DATA_PLUS0 and MFR_DATA_PLUS1 MFR_STATUS_PLUS0, and MFR_STATUS_PLUS1 Reading Fault Log Using Command Plus and MFR_DATA_PLUS0 Reading Energy Using MFR_COMMAND_PLUS and MFR_DATA_PLUS0 Peek Operation Using MFR_DATA_PLUS0 Enabling and Disabling Poke Operations Poke Operation Using Mfr_data_plus0 Command Plus Operations Using MFR_DATA_PLUS1 On/Off Control, Margining and Configuration OPERATION ON_OFF_CONFIG MFR_CONFIG_LTC2972 Cascade Sequence ON with Time-Based Sequence OFF MFR_CONFIG2_LTC2972 MFR_CONFIG3_LTC2972 Tracking Supplies On and Off Tracking Implementation MFR_CONFIG_ALL_LTC2972 Programming User EEPROM Space STORE_USER_ALL and RESTORE_USER_ALL MFR_EE_UNLOCK MFR_EE_ERASE MFR_EE_DATA Response When Part Is Busy MFR_EE Erase and Write Programming Time Input Voltage Commands and Limits VIN_ON, VIN_OFF, VIN_OV_FAULT_LIMIT, VIN_OV_WARN_LIMIT, VIN_UV_WARN_LIMIT and VIN_UV_FAULT_LIMIT INPUT Current and ENERGY Energy Measurement and Reporting MFR_EIN MFR_EIN_CONFIG MFR_IIN_CAL_GAIN MFR_IIN_CAL_GAIN_TC MFR_CLEAR_ENERGY Output Voltage Commands and Limits VOUT_MODE VOUT_COMMAND, VOUT_MAX, VOUT_MARGIN_HIGH, VOUT_MARGIN_LOW, VOUT_OV_FAULT_LIMIT, VOUT_OV_WARN_LIMIT, VOUT_UV_WARN_LIMIT, VOUT_UV_FAULT_LIMIT, POWER_GOOD_ON and POWER_GOOD_OFF MFR_VOUT_DISCHARGE_THRESHOLD MFR_DAC_STARTUP MFR_DAC Output CURRENT Commands and Limits IOUT_CAL_GAIN and IOUT_CAL_OFFSET IOUT_OC_WARN_LIMIT MFR_IOUT_CAL_GAIN_TC External Temperature Commands and Limits OT_FAULT_LIMIT, OT_WARN_LIMIT, UT_WARN_LIMIT and UT_FAULT_LIMIT MFR_TEMP_1_GAIN and MFR_TEMP_1_OFFSET MFR_T_SELF_HEAT, MFR_IOUT_CAL_GAIN_TAU_INV and MFR_IOUT_CAL_GAIN_THETA Sequencing Timing Limits and Clock Sharing TON_DELAY, TON_RISE, TON_MAX_FAULT_LIMIT and TOFF_DELAY MFR_RESTART_DELAY Clock Sharing Watchdog Timer and Power Good MFR_PG_CONFIG MFR_PG_GPO MFR_PWRGD_EN MFR_POWERGOOD_ASSERTION_DELAY Watchdog Operation MFR_WATCHDOG_T_FIRST and MFR_WATCHDOG_T Fault Responses Clearing Latched Faults VOUT_OV_FAULT_RESPONSE and VOUT_UV_FAULT_RESPONSE OT_FAULT_RESPONSE, UT_FAULT_RESPONSE, VIN_OV_FAULT_RESPONSE and VIN_UV_FAULT_RESPONSE TON_MAX_FAULT_RESPONSE MFR_RETRY_DELAY MR_RETRY_COUNT Shared External Faults MFR_FAULTB0_PROPAGATE and MFR_FAULTB1_PROPAGATE MFR_FAULTB0_RESPONSE and MFR_FAULTB1_RESPONSE Fault Warning and Status CLEAR_FAULTS STATUS_BYTE STATUS_WORD STATUS_VOUT STATUS_IOUT STATUS_INPUT STATUS_TEMPERATURE STATUS_CML STATUS_MFR_SPECIFIC MFR_PADS MFR_COMMON MFR_STATUS_2 MFR_FIRST_FAULT Telemetry READ_VIN READ_IIN READ_PIN READ_VOUT READ_IOUT MFR_IIN_PEAK READ_TEMPERATURE_2 READ_POUT MFR_READ_IOUT MFR_IOUT_SENSE_VOLTAGE MFR_VIN_PEAK MFR_TEMPERATURE_1_MIN Fault Logging Fault Log Operation MFR_FAULT_LOG_STORE MFR_FAULT_LOG_RESTORE MFR_FAULT_LOG_CLEAR MFR_FAULT_LOG_STATUS MFR_FAULT_LOG MFR_FAULT_LOG Read Example Identification/Information CAPABILITY PMBUS_REVISION MFR_SPECIAL_ID MFR_SPECIAL_LOT MFR_INFO User Scratchpad USER_DATA_00, USER_DATA_01, USER_DATA_02, USER_DATA_03, USER_DATA_04 and MFR_LTC_RESERVED_2 Applications Information Overview Powering the LTC2972 Setting Command Register Values MEASURING INPUT CURRENT MEASURING INPUT VOLTAGE MEASURING INPUT POWER Measuring INPUT ENERGY Sequence, Servo, Margin and Restart Operations Command Units On or Off On Sequencing On State Operation Servo Modes DAC Modes Margining Off Sequencing VOUT Off Threshold Voltage Automatic Restart via MFR_RESTART_DELAY Command and CONTROL Pin Fault Management Output Overvoltage and Undervoltage Faults Output Overvoltage, Undervoltage, and Overcurrent Warnings Configuring the AUXFAULTB Output Multi-Channel Fault Management Interconnect Between Multiple ADI POWER MANAGERS Application Circuits Trimming and Margining DC/DC Converters with External Feedback Resistors Four-Step Resistor Selection Procedure for DC/DC Converters with External Feedback Resistors Trimming and Margining DC/DC Converters with a TRIM Pin Two-Step Resistor and DAC Full-Scale Voltage Selection Procedure for DC/DC Converters with a TRIM Pin Measuring Output with a Sense Resistor Measuring Output with Inductor DCR Single Phase Design Example Measuring Multiphase Currents Measuring Output Current in Buffered IMON Telemetry Mode LT3086 IMON Design Example Anti-Aliasing Filter Considerations Sensing Negative Voltages Connecting the DC1613 USB to I2C/SMBus/PMBus Controller to the LTC2972 in System Accurate DCR Temperature Compensation LTpowerPlay: An Interactive GUI for Power Managers PCB Assembly and Layout Suggestions Bypass Capacitor Placement Exposed Pad Stencil Design PCB Board Layout Unused ADC Sense Inputs Design Checklist I2C Output Enables VIN Sense Input Current Sense External Temperature Sense Logic Signals Unused Inputs DAC Outputs Package Description Revision History Typical Application Related Parts