SLLS872J January   2008  – March 2023 SN65HVD1785 , SN65HVD1786 , SN65HVD1787 , SN65HVD1791 , SN65HVD1792 , SN65HVD1793

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Product Selection Guide
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings (1)
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Thermal Considerations
    7. 7.7 Switching Characteristics
    8. 7.8 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
      1. 9.3.1 Hot-Plugging
      2. 9.3.2 Receiver Failsafe
      3. 9.3.3 70-V Fault-Protection
      4. 9.3.4 Additional Options
    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
        1. 10.2.1.1 Data Rate and Bus Length
        2. 10.2.1.2 Stub Length
        3. 10.2.1.3 Receiver Failsafe
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
  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
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support 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

10.2.1.1 Data Rate and Bus Length

There is an inverse relationship between data rate and cable length, which means the higher the data rate, the short the cable length; and conversely, the lower the data rate, the longer the cable length. While most RS-485 systems use data rates between 10 kbps and 100 kbps, some applications require data rates up to 250 kbps at distances of 4000 feet and longer. Longer distances are possible by allowing for small signal jitter of up to 5 or 10%.

GUID-A2FE185C-13C7-4794-8B82-CD5209C26CE7-low.gifFigure 10-3 Cable Length vs Data Rate Characteristic

Even higher data rates are achievable (for example, 10 Mbps for the SN65HVD1787 and SN65HVD1793) in cases where the interconnect is short enough (or has suitably low attenuation at signal frequencies) to not degrade the data.