DUAL-BIT DUAL-SUPPLY BUS TRANSCEIVER WITH CONFIGURABLE VOLTAGE TRANSLATION

DESCRIPTION

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 U74LVC2T45 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 always is active and must have a logic HIGH

or LOW level applied to prevent excess ICC and ICCZ.

The U74LVC2T45 is designed so that the DIR input circuit is

supplied by VCCA. 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 ensures that if either VCC input is at

GND, both ports are in the high-impedance state.

FEATURES

* Fully Configurable Dual-Rail Design Allows Each Port to Operate

Over the Full 1.65-V to 5.5-V Power-Supply Range

* VCC Isolation Feature: If Either VCC Input Is at GND, Both Ports

Are in the High-Impedance State

* ±24mA Output Drive at 3.3V

* IOFF Supports Partial-Power-Down Mode Operation