74LVC245A

The 74LVC245A is an octal bus transceiver with 3-state outputs, which can accept supply voltage range from 1.65V to 3.6V. The device is mainly used for asynchronous communication between data buses. Both 3.3V and 5V devices can drive inputs, enabling this device to operate as translator in a mixed 3.3V and 5V system environment.

The An and Bn are 8-bit data input-output ports, DIR is the direction control input and OE is the output enable input. When DIR is set high, it allows transmission from An to Bn. When DIR is set low, it allows transmission from Bn to An. OE can be used to make the outputs disabled so that the buses are effectively isolated.

OE should be connected to VCC by using a pull-up resistor to ensure the high-impedance state in the period of power-up or power-down, and the minimum resistance depends on the current-sinking capability of the driver.

This device is highly suitable for partial power-down applications using power-off leakage current (IOFF) circuit. When the device is powered down, the current backflow will be prevented from passing through the device.