8.1 Overview

The SN74ALVCH16245 device is designed for asynchronous communication between two data buses. The logic levels of the direction-control (DIR) input and the output-enable (OE) input activate either the B-port outputs or the A-port outputs or place both output ports into the high-impedance mode. 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 is always active and must have a logic high or low level applied to prevent excess I_CC and I_CCZ.

To ensure the high-impedance state during power up or power down, OE should be tied to V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.

8.2 Functional Block Diagrams

8.3 Feature Description

The input tolerance of 5.5V inputs allows the device to be used in down voltage translation applications as well for example if translation is required from 5 V to 3.3 V or 1.8 V. Also bus hold on data inputs eliminates the need for external pullup or pulldown resistors to be used, enabling customer to save board space and system cost.

8.4 Device Functional Modes

Table 1 lists the functional modes for SN74ALVCH16245.