LTC3882_15 Datasheet, PDF (77/104 Pages) Linear Technology – Dual Output PolyPhase Step-Down DC/DC Voltage Mode Controller with Digital Power System Management

LTC3882
PMBus COMMAND DETAILS (Output Voltage and Limits)
VOUT_MAX
The VOUT_MAX command sets an upper limit, in volts, on the allowed value of any command that sets the output
voltage, including VOUT_MARGIN_HIGH. Setting VOUT_MAX to a value greater than MFR_VOUT_MAX will result in
a CML fault and VOUT_MAX will be set to the value of MFR_VOUT_MAX. A VOUT_MAX warning may also be gener-
ated if VOUT_MAX is set above 5.5V in output range 0 or above 2.75V in range 1. This command ensures that any
combination of commands attempting to set V_OUT above VOUT_MAX will result in a warning with the output clamped
at VOUT_MAX. When a VOUT_MAX warning occurs, the device takes the following actions:
• Sets The Offending Command Value to the Voltage Specified by VOUT_MAX
• Sets the VOUT Bit in the STATUS_WORD
• Sets the VOUT_MAX Warning Bit in the STATUS_VOUT Command
• Notifies the Host by Asserting ALERT, Unless Masked
This command has two data bytes in Linear_16u format.
MFR_VOUT_AVP
The MFR_VOUT_AVP command sets the change in output voltage, in percent, for a full-scale change in output current.
MFR_VOUT_AVP can be used for active voltage positioning (AVP) requirements or passive current sharing schemes.
The LTC3882 interprets the IOUT_OC_WARN_LIMIT value as full-scale current for AVP. If MFR_VOUT_AVP is non-zero,
VOUT_COMMAND sets the maximum, no-load output voltage and servo mode for that channel is automatically dis-
abled. Setting MFR_VOUT_AVP to 0.0% automatically disables the AVP function. Refer to the Applications Information
section for additional details on range and resolution when using MFR_VOUT_AVP.
This command has two data bytes in Linear_5s_11s format.
VOUT_MARGIN_HIGH
The VOUT_MARGIN_HIGH command programs the output voltage, in volts, to be produced when Margin High is set
with the OPERATION command (no load value if AVP is enabled). The value must be greater than VOUT_ COMMAND.
This command has two data bytes in Linear_16u format.
VOUT_MARGIN_LOW
The VOUT_MARGIN_LOW command programs the output voltage, in volts, to be produced when Margin Low is set
by the OPERATION command (no load value if AVP is enabled). The value must be less than VOUT_COMMAND.
This command has two data bytes in Linear_16u format.
VOUT_OV_FAULT_LIMIT
The VOUT_OV_FAULT_LIMIT command sets the value of the output voltage measured by the OV supervisor at the V_SENSE±
pins, in volts, which causes an output overvoltage fault. If VOUT_OV_FAULT_LIMIT is modified while the channel is
on, 10ms should be allowed for the new value to take effect. Modifying V_OUT during that time can result an erroneous
OV fault. The LTC3882 sets MFR_COMMON bits[6:5] low while it establishes the new VOUT_OV_FAULT_LIMIT value.
This command has two data bytes in Linear_16u format.
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