SCLS746A February   2014  – October 2014 SN74GTL2014

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Dynamic Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 5 V tolerance on LVTTL input
      2. 8.3.2 3.6 V tolerance on GTL Input/Output
      3. 8.3.3 Ultra-Low VREF and High Bandwidth
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 GTL-/GTL/GTL+ to LVTTL
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 LVTTL/TTL to GTL-/GTL/GTL+
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Trademarks
    2. 12.2 Electrostatic Discharge Caution
    3. 12.3 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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発注情報

9 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.

9.1 Application Information

GTL2014 is the voltage translator for GTL–/GTL/GTL+ to LVTTL or LVTTL to GTL–/GTL/GTL+. Please find the reference schematic and recommend value for passive component in the Typical Application.

9.2 Typical Application

9.2.1 GTL–/GTL/GTL+ to LVTTL

Select appropriate VTT/VREF based upon GTL–/GTL/GTL+. The parameters in Recommended Operating Conditions are compliant to the GTL specification.

App_GTL_LVTTL_scls746.gifFigure 5. Application Diagram for GTL to LVTTL

9.2.1.1 Design Requirements

The GTL2014 requires industrial standard LVTTL and GTL inputs. The design example in Application Information show standard voltage level and typical resistor values.

NOTE

Only LVTTL terminals (A1/A2/A3/A4) are tolerant to 5 V.

9.2.1.2 Detailed Design Procedure

To begin the design process, determine the following:

  1. Select direction base upon application (GTL–/GTL/GTL+ to LVTTL or LVTTL to GTL–/GTL/GTL+).
  2. Set up appropriate DIR pin and VREF/VTT.
  3. Choose correct pullup resistor value base upon data rate and driving current requirement (for LVTTL to GTL–/GTL/GTL+).

9.2.1.3 Application Curve

C005_SCLS746.pngFigure 6. GTL-to-LVTTL, VREF = 1 V, VIN = 1.5 V, 100 MHz

9.2.2 LVTTL/TTL to GTL–/GTL/GTL+

Because GTL is an open-drain interface, the selection of pullup resistor depends on the application requirement (for example, data rate) and PCB trace capacitance.

App_LVTTL_GTL_scls746.gifFigure 7. Application Diagram for LVTTL to GTL

9.2.2.1 Design Requirements

The GTL2014 requires industrial standard LVTTL and GTL inputs. The design example in the Application Information section show standard voltage level and typical resistor values.

NOTE

Only LVTTL terminals (A1/A2/A3/A4) are tolerant to 5 V.

9.2.2.2 Detailed Design Procedure

To begin the design process, determine the following:

  1. Select direction based upon application (GTL–/GTL/GTL+ to LVTTL or LVTTL to GTL–/GTL/GTL+).
  2. Set up appropriate DIR pin and VREF/VTT.
  3. Choose correct pullup resistor value base upon data rate and driving current requirement (for LVTTL to GTL–/GTL/GTL+).

9.2.2.3 Application Curve

C004_SCLS746.pngFigure 8. LVTTL-to-GTL, VREF = 1 V, VTT = 1.5 V, 10 MHz