Datasheet

LTC2977
27
2977fa
For more information www.linear.com/LTC2977
PMBus COMMAND SUMMARY
Summary Table
COMMAND NAME
CMD
CODE DESCRIPTION TYPE PAGED
DATA
FORMAT UNITS EEPROM
DEFAULT
VALUE
REF
PAGE
MFR_FAULT_LOG_
RESTORE
0xEB Command a transfer of the fault log
previously stored in EEPROM back to
RAM.
Send Byte N NA 67
MFR_FAULT_LOG_CLEAR 0xEC Initialize the EEPROM block reserved for
fault logging and clear any previous fault
logging locks.
Send Byte N NA 68
MFR_FAULT_LOG_STATUS 0xED Fault logging status. R Byte N Reg Y NA 68
MFR_FAULT_LOG 0xEE Fault log data bytes. This sequentially
retrieved data is used to assemble a
complete fault log. 256 Bytes: 0xFF
followed by 255 bytes of fault log data.
R Block N Reg Y NA 69
MFR_COMMON 0xEF Manufacturer status bits that are common
across multiple LT C chips.
R Byte N Reg NA 60
MFR_RETRY_COUNT 0xF7 Retry count for all faulted off conditions
that enable retry.
R/W Byte N Reg Y 0x07 55
MFR_VOUT_MIN 0xFB Minimum measured value of READ_
VOUT.
R Word Y L16 V NA 61
MFR_VIN_MIN 0xFC Minimum measured value of READ_VIN. R Word N L11 V NA 61
MFR_TEMPERATURE_MIN 0xFD Minimum measured value of READ_
TEMPERATURE_1.
R Word N L11 °C NA 61
Data Formats
L11 Linear_5s_11s PMBus data field b[15:0]
Value = Y • 2
N
where N = b[15:11] is a 5-bit two’s complement integer and Y = b[10:0] is an 11-bit two’s complement integer
Example:
READ_VIN = 10V
For b[15:0] = 0xD280 = 1101_0010_1000_0000b
Value = 640 • 2
–6
= 10
See PMBus Spec Part II: Paragraph 7.1
L16
Linear_16u PMBus data field b[15:0]
Value = Y • 2
N
where Y = b[15:0] is an unsigned integer and N = Vout_mode_parameter is a 5-bit two’s complement
exponent that is hardwired to –13 decimal.
Example:
VOUT_COMMAND = 4.75V
For b[15:0] = 0x9800 = 1001_1000_0000_0000b
Value = 38912 • 2
–13
= 4.75
See PMBus Spec Part II: Paragraph 8.3.1
Reg Register PMBus data field b[15:0] or b[7:0].
Bit field meaning is defined in detailed PMBus Command Register Description.