Datasheet

LTC3880/LTC3880-1
83
3880fc
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PMBus COMMAND DETAILS
Table 6. VOUT_UV_FAULT_RESPONSE Data Byte Contents
BITS DESCRIPTION VALUE MEANING
7:6 Response
For all values of bits [7:6], the LTC3880:
• 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 RUNn pin, the
OPERATION command, or the combined action of the RUNn pin
and OPERATION command, to turn off and then to turn back on,
or
• Bias power is removed and reapplied to the LTC3880
00 The PMBus device continues operation without interruption.
(Ignores the fault functionally)
01 The PMBus device continues operation for the delay time
specified by bits [2:0] and the delay time unit specified for
that particular fault. If the fault condition is still present at the
end of the delay time, the unit responds as programmed in the
Retry Setting (bits [5:3]).
10 The device shuts down (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.
5:3 Retry Setting 000-110 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 RUNn 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 The delay time in 10µs increments. This delay time determines
how long the controller continues operating after a fault is
detected. Only valid for deglitched off state.
TON_MAX_FAULT_RESPONSE
The TON_MAX_FAULT_RESPONSE command instructs the device on what action to take in response to a TON_MAX
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
• Sets the VOUT bit in the STATUS_WORD
• Sets the TON_MAX_FAULT bit in the STATUS_VOUT command, and
• Notifies the host by asserting ALERT pin
• A value of 0 disables the TON_MAX_FAULT_RESPONSE. It is not recommended to use 0.
This command has one data byte.