SCES553H May 2004 – November 2020 SN74AVC32T245
This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.
The VCC isolation feature ensures that if either VCC input is at GND, then both ports are in the high-impedance state.
To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.