SN74LVT244BDW (TEXAS INSTRUMENTS)

The SN74LVT244BDW is an octal Buffer/Line Driver designed specifically for low-voltage (3.3V) VCC operation, but with the capability to provide a TTL interface to a 5V system environment. It is organized as two 4-bit line drivers with separate output-enable (OE) inputs. When OE is low, the device passes data from the A inputs to the Y outputs. When OE is high, the outputs 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 pull-up resistor and the minimum value of the resistor is determined by the current-sinking capability of the driver. It is fully specified for hot-insertion applications using IOFF and power-up 3-state. The IOFF circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down. The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down, which prevents driver conflict.