SN74AC245N .

The SN74AC245N is an octal Bus Transceiver with 3-state outputs. It is designed for asynchronous 2-way communication between data buses. The control-function implementation minimizes external timing requirements. When the output-enable (OE)\ is low, the device passes non-inverted data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction control (DIR) input. A high on OE\ disables the device so that the buses are effectively isolated. To ensure the high-impedance state during power up or power down, OE\ should be tied to VCC through a pull-up resistor and the minimum value of the resistor is determined by the current-sinking capability of the driver.