SLVSFZ1 December 2020 TPS27SA08-Q1
The ground protection network will cause the device ground to be at a higher potential than the module ground (and microcontroller ground). This offset will impact the interface between the device and the microcontroller.
Logic pin voltage will be offset by the forward voltage of the diode. For input pins (for example, EN), the designer must consider the VIH specification of the switch and the VOH specification of the microcontroller. For a system that does not include DGND, it is required that VOH > VIH. For a system that does include DGND, it is required that VOH > (VIH + VF). VF is the forward voltage of DGND.
For use of the status pin, ST, a similar consideration is necessary. The designer must consider the VOL, ST specification and the VIL specification of the microcontroller. For a system that includes DGND, it is required that VOL, ST + VF < VIL, µC.
The sense resistor, RSNS, should be terminated to the microcontroller ground. In this case, the ADC can accurately measure the SNS signal even if there is an offset between the microcontroller ground and the device ground.