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If Vbb of AMIS-305x2 is disconnected there will be no Vdd voltage (internal voltage regulator not powered). If the microcontroller controlling the motor driver is supplied by another power supply (5V or 3.3V), it is possible that a voltage is applied to one of the motor driver IO?s. Is this a problem?
In case the motor driver (AMIS-305x2) is not powered (no Vbb) there will be no Vdd voltage. If the microcontroller would be supplied by this Vdd voltage, the microcontroller will not be powered so there will also be no voltage on one of the IO pins of the motor driver. So no issue in this case. If however the motor driver does not supply the microcontroller (microcontroller is supplied by an external power supply), it is possible that when Vbb of AMIS-305x2 is not powered, the microcontroller still is. It is however no issue that in this situation a voltage is supplied to the motor driver IOs.
Answered by: ON Semiconductor
2011-06-15 17:56:22.0