Datasheet

LTC3880/LTC3880-1
71
3880fc
For more information www.linear.com/LTC3880
PMBus COMMAND DETAILS
Output Voltage and Limits
COMMAND NAME CMD CODE DESCRIPTION TYPE PAGED
DATA
FORMAT UNITS NVM
DEFAULT
VALUE
VOUT_MODE 0x20 Output voltage format and exponent (2
–12
). R Byte Y Reg 2
–2
0x14
VOUT_MAX 0x24 Upper limit on the commanded output voltage
including VOUT_MARGIN_HIGH.
R/W Word
Y L16 V Y 4.096 Ch0
0x4189
5.5 Ch1
0x5800
VOUT_OV_FAUL
T_ LIMIT 0x40 Output overvoltage fault limit. R/W Word Y L16 V Y 1.1
0x119A
VOUT_OV_WARN_ LIMIT 0x42 Output overvoltage warning limit. R/W Word Y L16 V Y 1.075
0x1133
VOUT_MARGIN_HIGH 0x25 Margin high output voltage set point. Must be
greater than VOUT_COMMAND.
R/W Word Y L16 V Y 1.05
0x10CD
VOUT_COMMAND 0x21 Nominal output voltage set point. R/W Word Y L16 V Y 1.0
0x1000
VOUT_MARGIN_LOW 0x26 Margin low output voltage set point. Must be
less than VOUT_COMMAND.
R/W Word Y L16 V Y 0.95
0x0F33
VOUT_UV_WARN_ LIMIT 0x43 Output undervoltage warning limit. R/W Word Y L16 V Y 0.925
0x0ECD
VOUT_UV_FAULT_ LIMIT 0x44 Output undervoltage fault limit. R/W Word Y L16 V Y 0.9
0x0E66
POWER_GOOD_ON 0x5E Output voltage at or above which a power
good should be asserted.
R/W Word Y L16 V Y 0.93
0x0EE1
POWER_GOOD_OFF 0x5F Output voltage at or below which a power
good should be de-asserted.
R/W Word Y L16 V Y 0.92
0x0EB8
MFR_VOUT_MAX 0xA5 Maximum allowed voltage command
including VOUT_OV_FAULT_LIMIT.
R Word Y L16 V 4.096 Ch0
5.5 Ch1
VOUT_MODE
The data byte for VOUT_MODE command, used for commanding and reading output voltage, consists of a 3-bit mode
(only linear format is supported) and a 5-bit parameter representing the exponent used in output voltage Read/Write
commands.
This read-only command has one data byte
VOUT_MAX
The VOUT_MAX command sets an upper limit on the output voltage, including VOUT_MARGIN_HIGH, the unit can
command regardless of any other commands or combinations.
This command has two data bytes and is formatted in Linear_16u format.
VOUT_OV_FAULT_LIMIT
The VOUT_OV_FAULT_LIMIT command sets the value of the output voltage measured at the sense pins, in volts, which
causes an output overvoltage fault.
If the VOUT_OV_FAULT_LIMIT is modified and the switcher is active, allow 10ms after the command is modified to
assure the new value is being honored. The part indicates if it is busy making a calculation. Monitor bits 5 and 6 of