9.1 Overview

The SN74LVCR16245A device is designed for asynchronous communication between 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 always is active and must have a logic HIGH or LOW level applied to prevent excess I_CC and I_CCZ.

All inputs and outputs have equivalent 26-Ω resistors that will slow the edges of the output and reduce switching noise caused by long capacitive etch runs or cables.

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. Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of these devices as translators in a mixed 3.3-V/5-V system environment.

This device is fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

9.2 Functional Block Diagram

Figure 4. Logic Diagram (Positive Logic)

9.3 Feature Description

• Wide operating voltage range
  • Operates from 1.65 V to 3.6 V
• Allows down voltage translation
  • Inputs accept voltages to 5.5 V
• I_off feature
  • Allows voltages on the inputs and outputs when V_CC is 0 V

9.4 Device Functional Modes