LTC3883 Datasheet, PDF (88/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
PMBus Command Details
This condition is detected by the ADC so the response time may be up to 120ms.
This command has one data byte.
UT_FAULT_RESPONSE
The UT_FAULT_RESPONSE command instructs the device on what action to take in response to an external under-
temperature 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 Undertemperature Fault bit in the STATUS_TEMPERATURE command, and
• Notifies the host by asserting ALERT pin
This condition is detected by the ADC so the response time may be up to 120ms.
This command has one data byte.
Table 9. Data Byte Contents: TON_MAX_FAULT_RESPONSE, VIN_OV_FAULT_RESPONSE,
OT_FAULT_RESPONSE, UT_FAULT_RESPONSE
BITS DESCRIPTION
VALUE MEANING
7:6 Response
00 The PMBus device continues operation without interruption.
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:
01 Not supported. Writing this value will generate a CML fault.
10 The device shuts down immediately (disables the output) and
responds according to the retry setting in bits [5:3].
11 Not supported. Writing this value will generate a CML fault.
• 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
000 The unit does not attempt to restart. The output remains
disabled until the fault is cleared until the device is commanded
OFF bias power is removed.
111 The PMBus device attempts to restart continuously, without
limitation, until it is commanded OFF (by the RUN pin or
OPERATION command or both), bias power is removed, or
another fault condition causes the unit to shut down without
retry. Note: The retry interval is set by the MFR_RETRY_DELAY
command.
2:0 Delay Time
XXX Not supported. Values ignored
Fault Sharing
Fault Sharing Propagation
COMMAND NAME
MFR_GPIO_
PROPAGATE_LTC3883
CMD CODE DESCRIPTION
0xD2 Configuration that determines which faults are
propagated to the GPIO pins.
DATA
TYPE FORMAT
R/W Word Reg
UNITS
88
DEFAULT
NVM VALUE
Y
0x2993
3883f