LTC3883 Datasheet, PDF (82/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
PMBus Command Details
MFR_RESTART_DELAY
This command specifies the minimum RUN off time in milliseconds. This device will pull the RUN pin low for this length
of time once a falling edge of RUN has been detected. The minimum recommended value is 136ms.
Note: The restart delay is different than the retry delay. The restart delay pulls RUN low for the specified time, after
which a standard start-up sequence is initiated. The minimum restart delay should be equal to TOFF_DELAY + TOFF_
FALL + 136ms. Valid values are from 136ms to 65.52 seconds in 16ms increments. To assure a minimum off time,
set the MFR_RESTART_DELAY 16mS longer than the desired time. The output rail can be off longer than the MFR_
RESTART_DELAY after the RUN pin is pulled high if the output decay bit 0 is enabled in MFR_CHAN_CONFIG_LTC3883
and the output takes a long time to decay below 12.5% of the programmed value.
This command has two data bytes and is formatted in Linear_5s_11s format.
Fault Response
Fault Responses All Faults
COMMAND NAME
MFR_RETRY_ DELAY
CMD CODE DESCRIPTION
0xDB Retry interval during FAULT retry mode.
TYPE
R/W Word
DATA
FORMAT
L11
UNITS
ms
DEFAULT
NVM VALUE
Y
350
0xFABC
MFR_RETRY_DELAY
This command sets the time in milliseconds between retries if the fault response is to retry the controller at specified
intervals. This command value is used for all fault responses that require retry. The retry time starts once the fault has
been detected by the offending channel. Valid values are from 120ms to 83.88 seconds in 10µs increments.
Note: The retry delay time is determined by the longer of the MFR_RETRY_DELAY command or the time required
for the regulated output to decay below 12.5% of the programmed value. If the natural decay time of the output is
too long, it is possible to remove the voltage requirement of the MFR_RETRY_DELAY command by asserting bit 0 of
MFR_CHAN_CONFIG_LTC3883.
This command has two data bytes and is formatted in Linear_5s_11s format.
Fault Responses Input Voltage
COMMAND NAME
VIN_OV_FAULT_RESPONSE
CMD CODE DESCRIPTION
0x56 Action to be taken by the device when an
input supply overvoltage fault is detected.
TYPE
R/W Byte
DATA
FORMAT
Reg
UNITS
DEFAULT
NVM VALUE
Y
0x80
VIN_OV_FAULT_RESPONSE
The VIN_OV_FAULT_RESPONSE command instructs the device on what action to take in response to an input over-
voltage fault. The data byte is in the format given in Table 9.
The device also:
• Sets the NONE_OF_THE_ABOVE bit in the STATUS_BYTE
• Set the INPUT bit in the upper byte of the STATUS_WORD
3883f
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