LTC3883 Datasheet, PDF (87/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
PMBus Command Details
MFR_OT_FAULT_RESPONSE
The MFR_OT_FAULT_RESPONSE command byte instructs the device on what action to take in response to an internal
overtemperature fault. The data byte is in the format given in Table 8.
The LTC3883 also:
• Sets the NONE_OF_THE_ABOVE bit in the STATUS_BYTE
• Sets the MFR bit in the STATUS_WORD, and
• Sets the Overtemperature Fault bit in the STATUS_MFR_SPECIFIC command
• Notifies the host by asserting ALERT pin
This command has one data byte.
Table 8. Data Byte Contents MFR_OT_FAULT_RESPONSE
BITS DESCRIPTION
7:6 Response
For all values of bits [7:6], the LTC3883:
• Sets the corresponding fault bit in the status commands and
• Notifies the host by asserting ALERT pin
The fault bit, once set, is cleared only when one or more of the
following events occurs:
• The device receives a CLEAR_FAULTS command
• The output is commanded through the RUN pin, the OPERATION
command, or the combined action of the RUN pin and
OPERATION command, to turn off and then to turn back on, or
• Bias power is removed and reapplied to the LTC3883
5:3 Retry Setting
2:0 Delay Time
VALUE
00
01
10
11
000
001-111
XXX
MEANING
Not supported. Writing this value will generate a CML fault.
Not supported. Writing this value will generate a CML fault
The device shuts down immediately (disables the output) and
responds according to the retry setting in bits [5:3].
The device’s output is disabled while the fault is present.
Operation resumes and the output is enabled when the fault
condition no longer exists.
The unit does not attempt to restart. The output remains
disabled until the fault is cleared.
Not supported. Writing this value will generate CML fault.
Not supported. Value ignored
Fault Responses External Temperature
COMMAND NAME
OT_FAULT_ RESPONSE
UT_FAULT_ RESPONSE
CMD CODE DESCRIPTION
0x50 Action to be taken by the device when an external
overtemperature fault is detected,
0x54 Action to be taken by the device when an external
undertemperature fault is detected.
TYPE
R/W Byte
R/W Byte
DATA
FORMAT
Reg
Reg
UNITS
DEFAULT
NVM VALUE
Y
0xB8
Y
0xB8
OT_FAULT_RESPONSE
The OT_FAULT_RESPONSE command instructs the device on what action to take in response to an external overtem-
perature fault on the external temp sensors. The data byte is in the format given in Table 9.
The device also:
• Sets the TEMPERATURE bit in the STATUS_BYTE
• Sets the Overtemperature Fault bit in the STATUS_TEMPERATURE command, and
• Notifies the host by asserting ALERT pin
3883f
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