The SN74AVCB164245 is designed so that the control pins (1DIR, 2DIR, 1OE, and 2OE) are supplied by VCCB. To ensure the high-impedance state during power up or power down, OE should be tied to VCCB through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver. 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. If either VCC input is at GND, both ports are in the high-impedance state. ORDERING INFORMATION