Datasheet
LTC2974
44
2974fc
For more information www.linear.com/LTC2974
pMbus coMManD DescripTion
VOUT_MODE
This command is read only and specifies the mode and exponent for all commands with a L16 data format. See
Data Formats on page 27.
VOUT_MODE Data Contents
BIT(S) SYMBOL OPERATION
b[7:5] Vout_mode_type Reports linear mode. Hard-wired to 000b.
b[4:0] Vout_mode_parameter Linear mode exponent. 5-bit two’s complement integer. Hardwired to 0x13 (–13 decimal).
OUTPUT VOLTAGE COMMANDS AND LIMITS
COMMAND NAME
CMD
CODE DESCRIPTION TYPE PAGED FORMAT UNITS EEPROM
DEFAULT
VALUE
REF
PAGE
VOUT_MODE 0x20 Output voltage data format and mantissa
exponent (2–
13)
.
R Byte Y Reg 0x13
44
VOUT_COMMAND 0x21 Servo target. Nominal DC/DC converter
output voltage setpoint.
R/W Word Y L16 V Y 1.0
0x2000
45
VOUT_MAX 0x24 Upper limit on the output voltage the unit
can command regardless of any other
commands.
R/W Word Y L16 V Y 4.0
0x8000
45
VOUT_MARGIN_HIGH 0x25 Margin high DC/DC converter output voltage
setting.
R/W Word Y L16 V Y 1.05
0x219A
45
VOUT_MARGIN_LOW 0x26 Margin low DC/DC converter output voltage
setting.
R/W Word Y L16 V Y 0.95
0x1E66
45
VOUT_OV_FAULT_LIMIT 0x40 Output overvoltage fault limit. R/W Word Y L16 V Y 1.1
0x2333
45
VOUT_OV_WARN_LIMIT 0x42 Output overvoltage warning limit. R/W Word Y L16 V Y 1.075
0x2266
45
VOUT_UV_WARN_LIMIT 0x43 Output undervoltage warning limit. R/W Word Y L16 V Y 0.925
0x1D9A
45
VOUT_UV_FAULT_LIMIT 0x44 Output undervoltage fault limit. Used for
Ton_max_fault and power good de-
assertion.
R/W Word Y L16 V Y 0.9
0x1CCD
45
POWER_GOOD_ON 0x5E Output voltage at or above which a power
good should be asserted.
R/W Word Y L16 V Y 0.96
0x1EB8
45
POWER_GOOD_OFF 0x5F Output voltage at or below which a power
good should be de-asserted when Mfr_
config_all_pwrgd_off_uses_uv is clear.
R/W Word Y L16 V Y 0.94
0x1E14
45
MFR_VOUT_DISCHARGE_
THRESHOLD
0xE9 Coefficient used to multiply VOUT_
COMMAND in order to determine V
OUT
off
threshold voltage.
R/W Word Y L11 Y 2.0
0xC200
45
MFR_DAC 0xE0 Manufacturer register that contains the code
of the 10-bit DAC.
R/W Word Y Reg N 0x0000
45