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STSPIN32G4 separate control and motor supplies


I developed a board for 3 ph motor control with a quadrature encoder that seems to work fine. Now my client would like to modify it to use separate supplies for control/logic and motor as is standard practice in the PLC/automation world.

There are a couple of ways of doing this (in order of preference):

1) Power the STM32G431 die from the logic supply and the drive die and motor from the motor supply

2) Power the STSPIN32G4 from the logic supply and the motor from the motor supply.

3) Treat everything associated with the STSPIN32G4 and motor as a 'motor power domain' (not preferred)

Thinking about approach #1:

Figure 1 on page 3 of the data sheet is not super helpful.

It shows VDD on both dies without a strong indication of how it gets from one to the other.

Perhaps they are separate, one coming in on the VDD/VDDA pin of the left hand die and another one coming in on REG3V3/VDD of the right hand die because they are actually different nets?


Power sequencing becomes a consideration.

Has anyone done this/considered this or developed recommendations ?