Hi,
Assume the internal FET(s) that bucks the voltage down for the DC/DC got stuck on. I would like to calculate the current through the DC/DC inductor when it reaches it's DC state. To do this I need know the resistance characteristics of the current path between VDD and GND that runs through the DC/DC inductor when the FET(s) is active.
Preferably this data would be in the form of a plot of static drain source on resistance (current vs Rds(on)). Please share this data if you have it.
Thanks,
A buck converter is a series configuration. There is no quiescent current if the fet is stuck on. If it were to stay on the 1.8V rail would rise to VDD through a time constant determined by the 1.8V load activity, to a minor extent the FET Rds since it is so small and the size of the buck inductor. After this the 1.8V rail would forever be at VDD. This would likely destroy the components sitting on the 1.8V rail, but that is really a different problem. For reference, below is the wiki drawing of a classic buck converter:
