Datasheet

LTC2974
19
2974fc
For more information www.linear.com/LTC2974
operaTion
The LTC2974 always responds to its global address and the
SMBus Alert Response address regardless of the state of
its ASEL pins and the MFR_I2C_BASE_ADDRESS register.
Processing Commands
The LTC2974 uses a dedicated processing block to ensure
quick response to all of its commands. There are a few
EEPROM Related Commands
COMMAND TYPICAL DELAY* COMMENT
STORE_USER_ALL t
MASS_WRITE
See Electrical Characterization table. The LTC2974 will not accept any commands while it is transferring
register contents to the EEPROM. The command byte will be NACKed. MFR_COMMON may always be
read.
RESTORE_USER_ALL 30ms The LTC2974 will not accept any commands while it is transferring EEPROM data to command registers.
The command byte will be NACKed. MFR_COMMON may always be read.
MFR_FAULT_LOG_CLEAR 175ms The LTC2974 will not accept any commands while it is initializing the fault log EEPROM space. The
command byte will be NACKed. MFR_COMMON may always be read.
MFR_FAULT_LOG_STORE 20ms The LTC2974 will not accept any commands while it is transferring fault log RAM buffer to EEPROM
space. The command byte will be NACKed. MFR_COMMON may always be read.
Internal Fault log 20ms An internal fault log event is a one time event that uploads the contents of the fault log to EEPROM in
response to a fault. Internal fault logging may be disabled. Commands received during this EEPROM
write are NACKed. MFR_COMMON may always be read.
MFR_FAULT_LOG_RESTORE 2ms The LTC2974 will not accept any commands while it is transferring EEPROM data to the fault log RAM
buffer. The command byte will be NACKed. MFR_COMMON may always be read.
*The typical delay is measured from the command’s stop to the next command’s start.
exceptions where the part will NACK a subsequent com-
mand because it is still processing the previous command.
These are summarized in the following tables. MFR_COM-
MON is a special command that may always be read even
when the part is busy
. This provides an alternate method
for a host to determine if the LTC2974 is busy.
Other Commands
COMMAND DELAY* COMMENT
MFR_CONFIG <50µs The LTC2974 will not accept any commands while it is completing this command. The command byte
will be NACKed. MFR_COMMON may always be read.
IOUT_CAL_GAIN <500µs The LTC2974 will not accept any commands while it is completing this command. The command byte
will be NACKed. MFR_COMMON may always be read.
*The typical delay is measured from the command’s stop to the next command’s start.
Other PMBus Timing Notes
COMMAND COMMENT
CLEAR_FAULTS The LTC2974 will accept commands while it is completing this command but the affected status flags will not be cleared for
up to 500µs.