SCLS382O September   1997  – September 2014 SN74LV245A

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  Handling Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Switching Characteristics, VCC = 2.5 V ± 0.2 V
    7. 7.7  Switching Characteristics, VCC = 3.3 V ± 0.3 V
    8. 7.8  Switching Characteristics, VCC = 5 V ± 0.5 V
    9. 7.9  Noise Characteristics
    10. 7.10 Operating Characteristics
    11. 7.11 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Related Links
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
    4. 13.4 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DGV|20
  • DB|20
  • NS|20
  • ZQN|20
  • DW|20
  • PW|20
  • RGY|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9 Detailed Description

9.1 Overview

The SNx4LV245A devices are designed for asynchronous communication between data buses. The device transmits data 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 be used to disable the device so the buses are effectively isolated.

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

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the devices when they are powered down.

9.2 Functional Block Diagram

Logic.gifFigure 4. Logic Diagram (Positive Logic)

9.3 Feature Description

  • Allows down voltage translation from 5 V to 3.3 V
    • Inputs accept voltage levels up to 5.5 V
  • Slow edge rates minimize output ringing

9.4 Device Functional Modes

Table 1. Function Table

INPUTS OPERATION
OE DIR
L L B data to A bus
L H A data to B bus
H X Isolation