LTC3882_15 Datasheet, PDF (80/104 Pages) Linear Technology – Dual Output PolyPhase Step-Down DC/DC Voltage Mode Controller with Digital Power System Management

LTC3882
PMBus COMMAND DETAILS (Output Timing, Delays, and Ramping)
OUTPUT TIMING, DELAYS, AND RAMPING
COMMAND NAME
CMD
CODE DESCRIPTION
DATA
DEFAULT
TYPE PAGED FORMAT UNITS NVM VALUE
MFR_RESTART_DELAY
0xDC Minimum time RUN pin is held low by the R/W Word Y
L11
ms l 500ms
LTC3882.
0xFBE8
TON_DELAY
0x60 Delay from RUN pin or OPERATION on
command to TON_RISE ramp start.
R/W Word Y
L11
ms l 0.0ms
0x8000
TON_RISE
0x61 Time for V_OUT to rise from 0V to
VOUT_COMMAND after TON_DELAY.
R/W Word Y
L11
ms l 8.0ms
0xD200
TON_MAX_FAULT_LIMIT
0x62 Maximum time for V_OUT to rise above
R/W Word Y
L11
ms l 10.0ms
VOUT_UV_FAULT_LIMIT after TON_DELAY.
0xD280
VOUT_TRANSITION_RATE
0x27 V_OUT slew rate for programmed output
changes.
R/W Word Y
L11 V/ms l 0.25V/ms
0xAA00
TOFF_DELAY
0x64 Delay from RUN pin or OPERATION off
command to TOFF_FALL ramp start.
R/W Word Y
L11
ms l 0.0ms
0x8000
TOFF_FALL
0x65 Time for V_OUT to fall to 0V from
VOUT_COMMAND after TOFF_DELAY.
R/W Word Y
L11
ms l 8.0ms
0xD200
TOFF_MAX_WARN_LIMIT
0x66 Maximum time for V_OUT to decay below
R/W Word Y
L11
ms l 150ms
12.5% of VOUT_COMMAND after TOFF_FALL
0xF258
completes.
Related commands: MFR_RETRY_DELAY, STATUS_VOUT, SMBALERT_MASK, TON_MAX_FAULT_RESPONSE, MFR_CHAN_CONFIG_LTC3882,
MFR_PWM_MODE_LTC3882
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
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 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 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 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.
3882f
80
For more information www.linear.com/LTC3882