Datasheet

LTC3883/LTC3883-1
74
3883fa
For more information www.linear.com/LTC3883
PMBus COMMAND DETAILS
POWER_GOOD_OFF
The POWER_GOOD_OFF command sets the output voltage at which the POWER_GOOD# status bit in the STATUS_WORD
command should be asserted. POWER_GOOD_OFF is detected with an A/D read resulting in latency of up to 120ms.
The POWER_GOOD_OFF value must be set lower than the POWER_GOOD_ON value.
At initial power up the state of the PGOOD pin will be high regardless of VOUT. If the proper state of low at power-up is
required, place a Schottky diode between RUN and PGOOD. The Anode must be tied to PGOOD and the Cathode to RUN.
The POWER_GOOD# status bit is masked from initiating an ALERT. The POWER_GOOD# status bit in the STATUS_WORD
command is always reflective of VOUT with respect to the POWER_GOOD threshold regardless of the RUN state. The
PGOOD pin state is controlled by the POWER_GOOD# status bit and is qualified by the RUN state.
This command has two data bytes and is formatted in Linear_16u format.
MFR_VOUT_MAX
The MFR_VOUT_MAX command is the maximum output voltage in volts the part can produce. If the output
voltage is
set
to high range (Bit 6 of MFR_PWM_CONFIG_LTC3883 set to a 0) MFR_VOUT_MAX is 5.5V. If the output voltage
is set to low range (Bit 6 of MFR_PWM_CONFIG_LTC3883 set to a 1) the MFR_VOUT_MAX is 2.75V. Entering a
VOUT_COMMAND value greater than this will result in a CML fault and the output voltage setting will be clamped to
the maximum level. This will also result in Bit 3 VOUT_MAX_Warning in the STATUS_VOUT command being set.
This read only command has 2 data bytes and is formatted in Linear_16u format.
CURRENT
Output Current Calibration
COMMAND NAME
CMD
CODE DESCRIPTION TYPE
DATA
FORMAT UNITS NVM
DEFAULT
VALUE
IOUT_CAL_GAIN 0x38 The ratio of the voltage at the current sense pins to the sensed
current. For devices using a fixed current sense resistor, it is
the resistance value in mΩ.
R/W Word L11 mΩ Y 1.8
0xBB9A
MFR_IOUT_CAL_GAIN_
TC
0xF6 Temperature coefficient of the current sensing element. R/W Word CF Y 3900
0x0F3C
MFR_T_SELF_HEA
T 0xB8 Reports the calculated self heat value attributed to the inductor. R Word L11 C NA
MFR_IOUT_CAL_GAIN_
TAU_INV
0xB9 Coefficient used to emulate thermal time constant. R/W Word L11 s
–1
Y 0.0
0x8000
MFR_IOUT_CAL_GAIN_
THET
A
0xBA Used to calculate the instance inductor self heating effect. R/W Word L11 C/W Y 0.0
0x8000
IOUT_CAL_GAIN
The IOUT_CAL_GAIN command is used to set the resistance value of the current sense resistor in milliohms. (see
also MFR_IOUT_CAL_GAIN_TC).
This command has two data bytes and is formatted in Linear_5s_11s format.
MFR_IOUT_CAL_GAIN_TC
The MFR_IOUT_CAL_GAIN_TC command allows the user to program the temperature coefficient of the IOUT_CAL_GAIN
sense
resistor or inductor DCR in ppm/°C.