SCAS294O JANUARY   1993  – June 2015 SN54LVC257A , SN74LVC257A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Options
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information: 16-Pin Packages
    5. 7.5  Thermal Information: 20-Pin Package
    6. 7.6  Electrical Characteristics
    7. 7.7  SN54LVC257A Switching Characteristics
    8. 7.8  SN74LVC257A Switching Characteristics
    9. 7.9  Operating Characteristics
    10. 7.10 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 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

10.1 Application Information

The SNx4LVC257A devices are useful for digital signal data selector or multiplexer applications.

10.2 Typical Application

The SNx4LVC257A devices use CMOS technology and have balanced output drive. These devices can be used for down level translation and multiplexer function as shown in Figure 4.

SN54LVC257A SN74LVC257A lvc257aappinfo.gifFigure 4. SNx4LVC257A Used as Level Translation and as a Multiplexer

10.2.1 Design Requirements

Take care to avoid bus contention because it can drive currents that would exceed maximum limits. The high drive will also create fast edges into light loads so routing and load conditions must be considered to prevent ringing.

10.2.2 Detailed Design Procedure

  1. Recommended Input Conditions
  2. Recommend Output Conditions
    • Load currents must not exceed (IO max) per output and must not exceed (continuous current through VCC or GND) total current for the part. These limits are in the Recommended Operating Conditions table.
    • Outputs must not be pulled above VCC.

10.2.3 Application Curves

SN54LVC257A SN74LVC257A graph_15_vol_v_ces794.gifFigure 5. Output Drive Current (IOL)
vs LOW-level Output Voltage (VOL)
SN54LVC257A SN74LVC257A graph_15_voh_v_ces794.gifFigure 6. Output Drive Current (IOH)
vs HIGH-level Output Voltage (VOH)