2-Bit Dual Supply Transceiver with Configurable Voltage-Level Shifting and 3-State Outputs

This dual-bit noninverting bus transceiver uses two separate configurable power-supply rails. The A port is designed to track VCCA. VCCA accepts any supply voltage from 1.65V to 5.5V. The B port is designed to track VCCB. VCCB accepts any supply voltage from 1.65V to 5.5V. This allows for universal low-voltage bidirectional translation between any of the 1.8V, 2.5V, 3.3V, and 5V voltage nodes.

The SN74LVC2T45 is designed for

asynchronous communication between two data buses. The logic levels

of the direction-control (DIR) input activate either the B-port

outputs or the A-port outputs. The device transmits data from the A

bus to the B bus when the B-port outputs are activated, and from the

B bus to the A bus when the A-port outputs are activated. The input

circuitry on both A and B ports are always active and must have a

logic HIGH or LOW level applied to prevent excess ICC and

ICCZ.

The SN74LVC2T45 is designed so that

VCCA supplies the DIR input circuit. 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.

The VCC isolation feature is designed

so that if either VCC input is at GND, both ports are in

the high-impedance state.