The SN74AXC4T774 is a four-bit non-inverting bus transceiver that uses two individually configurable power-supply rails. The device is operational with both VCCA and VCCB supplies as low as 0.65 V. The A port is designed to track VCCA, which accepts any supply voltage from 0.65 V to 3.6 V. The B port is designed to track VCCB, which also accepts any supply voltage from 0.65 V to 3.6 V. Additionally the SN74AXC4T774 is compatible with a single-supply system.
The SN74AXC4T774 device is designed for asynchronous communication between data buses. The device transmits data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level of the direction-control inputs (DIRx). The output-enable input ( OE) is used to disable the outputs so the buses are effectively isolated. The SN74AXC4T774 device is designed so the control pins (DIRx and OE) are referenced to VCCA.
To ensure the high-impedance state of the level shifter I/Os during power up or power down, the OE pin should be tied to VCCA through a pullup resistor.
This device is fully specified for partial-power-down applications using the Ioff current. The Ioff protection circuitry ensures that no excessive current is drawn from or to an input, output, or combined I/O that is biased to a specific voltage while the device is powered down.
The VCC isolation feature ensures that if either VCCA or VCCB is less than 100 mV, both I/O ports are set to the high-impedance state by disabling their outputs.
Glitch-free power supply sequencing allows either supply rail to be powered on or off in any order while providing robust power sequencing performance.