8.2.3 Restrictions for Power States

When power is not supplied to the device (DC/DC converter output and VDDIO are off at ground potential), voltage cannot be applied to the ATWILC3000A pins because each pin contains an ESD diode from the pin to supply. This diode turns on when voltage higher than one diode drop is supplied to the pin.

If voltage must be applied to the signal pads when the chip is in a low-power state, the VDDIO supply must be on, so the Power_Down state must be used. Similarly, to prevent the pin-to-ground diode from turning on, do not apply voltage that is more than one diode drop below the ground to any pin.