To Whom It May Concern,
Part of my design incorporates an LTC2977 PMBus manager where one DAC outputs feeds the SET node (nominally -5V) of LT3090, a negative voltage regulator. I would like to servo the DAC to maintain/margin the SET node at or near -5V. I'm confused how to assign register values in LTPowerPlay for negative VOUT_COMMAND, as I have not seen much documentation on this front.
Any help is much appreciated.
There are a few things that you need to do. The 2977 does not have the ability to natively sense and servo a negative supply.
To sense a negative rail, you can follow the datasheet recommendation…