Datasheet

LTC2974
3
2974fc
For more information www.linear.com/LTC2974
MFR_FAULTB0_RESPONSE and MFR_FAULTB1_
RESPONSE ................................................................60
Fault Warning and Status ............................................... 61
CLEAR_FAULTS .........................................................61
STATUS_BYTE ........................................................... 61
STATUS_WORD .........................................................62
STATUS_VOUT ..........................................................62
STATUS_IOUT ...........................................................63
STATUS_INPUT .........................................................63
STATUS_TEMPERATURE ...........................................63
STATUS_CML ............................................................ 64
STATUS_MFR_SPECIFIC ...........................................64
MFR_PADS ................................................................65
MFR_COMMON ......................................................... 65
Telemetry .......................................................................66
READ_VIN .................................................................67
READ_VOUT .............................................................. 67
READ_IOUT ............................................................... 67
READ_TEMPERATURE_1 ..........................................67
READ_TEMPERATURE_2 .......................................... 67
READ_POUT ..............................................................67
MFR_READ_IOUT ..................................................... 67
MFR_IOUT_SENSE_VOLTAGE ................................... 68
MFR_VIN_PEAK ........................................................69
MFR_VOUT_PEAK ..................................................... 69
MFR_IOUT_PEAK ...................................................... 69
MFR_TEMPERATURE_1_PEAK .................................69
MFR_VIN_MIN ..........................................................69
MFR_VOUT_MIN .......................................................69
MFR_IOUT_MIN ........................................................69
MFR_TEMPERATURE_1_MIN ...................................69
Fault Logging ................................................................. 70
Fault Log Operation ................................................... 70
MFR_FAULT_LOG_STORE ........................................70
MFR_FAULT_LOG_RESTORE ....................................70
MFR_FAULT_LOG_CLEAR ........................................ 71
MFR_FAULT_LOG_STATUS .......................................71
MFR_FAULT_LOG ......................................................71
MFR_FAULT_LOG Read Example .............................. 74
Identification/Information ..............................................78
CAPABILITY ...............................................................79
PMBus_REVISION .....................................................79
MFR_SPECIAL_ID ..................................................... 79
MFR_SPECIAL_LOT .................................................. 79
User Scratchpad .............................................................79
USER_DATA_00, USER_DATA_01, USER_DATA_02,
USER_DATA_03, USER_DATA_04, MFR_LTC_
RESERVED_1 and MFR_LTC_RESERVED_2 .............79
Applications Information ...................................... 80
Overview ........................................................................80
Powering the LTC2974 ...................................................80
Setting Command Register Values .................................80
Sequence, Servo, Margin and Restart Operations .........80
Command Units On or Off .........................................80
On Sequencing ..........................................................80
On State Operation ....................................................81
Servo Modes ............................................................. 81
DAC Modes ................................................................82
Margining ..................................................................82
Off Sequencing ..........................................................82
V
OUT
Off Threshold Voltage .......................................82
Automatic Restart via MFR_RESTART_DELAY
Command and CONTROL pin ....................................82
Fault Management ..........................................................82
Output Overvoltage, Undervoltage, Overcurrent, and
Undercurrent Faults ...................................................82
Output Overvoltage, Undervoltage, and Overcurrent
Warnings ...................................................................83
Configuring the AUXFAULTB Output ..........................83
Multi-Channel Fault Management .............................. 84
Interconnect Between Multiple LTC2974’s .....................84
Application Circuits ........................................................ 85
Trimming and Margining DC/DC Converters with
External Feedback Resistors .....................................85
Four-Step Resistor Selection Procedure for DC/DC
Converters with External Feedback Resistors ...........85
Trimming and Margining DC/DC Converters with a
TRIM Pin ....................................................................86
Two-Step Resistor and DAC Full-Scale Voltage
Selection Procedure for DC/DC Converters with a
TRIM Pin .................................................................... 87
Measuring Current with a Sense Resistor .................87
Measuring Current with Inductor DCR ......................87
Single Phase Design Example ...................................88
Measuring Multiphase Currents ................................88
Multiphase Design Example ......................................89
Anti-aliasing Filter Considerations .............................89
Sensing Negative Voltages ........................................ 89
Connecting the DC1613 USB to I
2
C/SMBus/PMBus
Controller to the LTC2974 in System ......................... 90
Accurate DCR Temperature Compensation .................... 91
LTpowerPlay: An Interactive GUI for Power Managers ...93
PCB Assembly and Layout Suggestions ........................94
Bypass Capacitor Placement .....................................94
Exposed Pad Stencil Design ...................................... 94
Unused ADC Sense Inputs .........................................94
PCB Board Layout .....................................................94
Package Description ........................................... 95
Typical Application ............................................. 96
Related Parts .................................................... 96
Table oF conTenTs