Output Timing, Delays, And Ramping; Mfr_Restart_Delay; Ton_Delay; Ton_Rise - Linear Technology Analog Devices LTC3882-1 Datasheet

PMBus COMMAND DETAILS

OUTPUT TIMING, DELAYS, AND RAMPING

COMMAND NAME

MFR_RESTART_DELAY

TON_DELAY

TON_RISE

TON_MAX_FAULT_LIMIT
VOUT_TRANSITION_RATE
TOFF_DELAY
TOFF_FALL
TOFF_MAX_WARN_LIMIT
Related commands: MFR_RETRY_DELAY, STATUS_VOUT, SMBALERT_MASK, TON_MAX_FAULT_RESPONSE, MFR_CHAN_CONFIG_LTC3882-1,
MFR_PWM_MODE_LTC3882-1
These commands can be used to establish required on/off sequencing for any number of system power supply rails.
MFR_RESTART_DELAY
The MFR_RESTART DELAY command specifies the minimum PWM off time (RUN low) in milliseconds. The LTC3882-1
will actively hold its RUN pin low for this length of time if a falling RUN edge is detected. After this delay, a standard
start-up sequence can be initiated. A minimum of TOFF_DELAY + TOFF_FALL + 136ms is recommended for this com-
mand value. Valid value range is 136ms to 65.52 seconds. The LTC3882-1 uses a resolution of 16ms for this command
and will not produce delays outside of this range.
This command has two data bytes in Linear_5s_11s format.
TON_DELAY
The TON_DELAY command sets the delay, in milliseconds, between a start condition and the beginning of the output
voltage rise. Values from 0ms to 83 seconds are considered valid, and the LTC3882-1 will not produce delays outside
of this range.
This command has two data bytes in Linear_5s_11s format.
TON_RISE
The TON_RISE command sets the desired time, in milliseconds, from the point the output starts to rise until it enters
the regulation band. Values from 0 seconds to 1.3 seconds are considered valid, and the LTC3882-1 will not produce
rise times outside of this range. Values of TON_RISE less than 0.25ms or resulting slopes greater than 4V/ms will
result in an output step to the commanded voltage limited only by PWM analog loop response.
This command has two data bytes in Linear_5s_11s format.
(Output Timing, Delays, and Ramping)
CMD
CODE DESCRIPTION
0xDC Minimum time RUN pin is held low by the
LTC3882-1.
0x60 Delay from RUN pin or OPERATION on
command to TON_RISE ramp start.
0x61 Time for V to rise from 0V to
OUT
VOUT_COMMAND after TON_DELAY.
0x62 Maximum time for V to rise above
OUT
VOUT_UV_FAULT_LIMIT after TON_DELAY.
0x27 V slew rate for programmed output
OUT
changes.
0x64 Delay from RUN pin or OPERATION off
command to TOFF_FALL ramp start.
0x65 Time for V to fall to 0V from
OUT
VOUT_COMMAND after TOFF_DELAY.
0x66 Maximum time for V to decay below
OUT
12.5% of VOUT_COMMAND after TOFF_FALL
completes.
For more information
TYPE PAGED
R/W Word Y
R/W Word Y
R/W Word Y
R/W Word Y
R/W Word Y
R/W Word Y
R/W Word Y
R/W Word Y
www.analog.com
LTC3882-1
DATA DEFAULT
FORMAT UNITS NVM VALUE
L11 ms 500ms
l
0xFBE8
L11 ms 0.0ms
l
0x8000
L11 ms 8.0ms
l
0xD200
L11 ms 10.0ms
l
0xD280
L11 V/ms 0.25V/ms
l
0xAA00
L11 ms 0.0ms
l
0x8000
L11 ms 8.0ms
l
0xD200
L11 ms 150ms
l
0xF258
83
Rev A