9.1 Overview

The SN74LVCH16373A is particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers. It can be used as two 8-bit latches or one 16-bit latch. When the latch-enable (LE) input is high, the Q outputs follow the data (D) inputs. When LE is taken low, the Q outputs are latched at the levels set up at the D inputs.

A buffered output-enable (OE) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines without interface or pull-up components.

OE does not affect internal operations of the latch. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

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 pull-up 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 holds unused or undriven inputs at a valid logic state. Use of pull-up or pull-down resistors with the bus-hold circuitry is not recommended.

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
• Bus hold on data inputs eliminates the need for external pull-up or pull-down resistors

9.4 Device Functional Modes