What happens if the FX3 chip is powered up with the VBUS pin floating? | Cypress Semiconductor
What happens if the FX3 chip is powered up with the VBUS pin floating?
I am developing a board with the FX3, powered only with 1.2V and 2.5V, respectively for the core supply and the VIOs supplies.
Since a 5V power supply is not available on my board, I would like to use the USB 5V supply coming from the connector to power the VBUS pin. The other power pins of the CYUSB3014, such as VDD and VIOs, are instead fed by other power supplies, independent from the USB 5V.
This means that when no USB cable is connected, the VBUS pin would be left floating while the other power pins of the chip would be powered with their respective supplies.
Is this condition acceptable without damaging the chip?
Is this condition acceptable also for the VBATT pin (e.g. connecting it to 5V supplied by USB cable)?