7.1 Overview

This 16-bit (dual-octal) noninverting bus transceiver is designed for 1.65-V to 3.6-V V_CC operation.

The SN74LVCHR16245A device is designed for asynchronous communication between data buses. The control-function implementation minimizes external-timing requirements.

This device can be used as two 8-bit transceivers or one 16-bit transceiver. It allows data transmission from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input can disable the device so that the buses are effectively isolated.

All outputs, which are designed to sink up to 12 mA, include equivalent 26-Ω series resistors to reduce overshoot and undershoot.

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

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.

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.

Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended. The bus-hold circuitry is part of the input circuit and is not disabled by OE or DIR.

7.2 Functional Block Diagram

Figure 4. Logic Diagram (Positive Logic)

7.3 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
• All outputs have equivalent 26-Ω series resistors, so no external resistors are required
• Bus hold on data inputs eliminates the need for external pullup or pulldown resistors

7.4 Device Functional Modes