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

12.1 Layout Guidelines

To ensure reliable operation at all data rates and supply voltages, each supply should be decoupled with a 100-nF ceramic capacitor located as close to the supply pins as possible. This helps to reduce supply voltage ripple present on the outputs of switched-mode power supplies and also helps to compensate for the resistance and inductance of the PCB power planes.

  1. Place the protection circuitry close to the bus connector to prevent noise transients from entering the board.
  2. Use VCC and ground planes to provide low-inductance power distribution. Note that high-frequency currents tend to follow the path of least inductance and not the path of least resistance.
  3. Design the protection components into the direction of the signal path. Do not force the transient currents to divert from the signal path to reach the protection device.
  4. Apply 100-nF-to-220-nF bypass capacitors as close as possible to the VCC pins of transceiver, UART, or controller ICs on the board.
  5. Use at least two vias for VCC and ground connections of bypass capacitors and protection devices to minimize effective via-inductance.
  6. Use 1-kΩ-to-10-kΩ pullup and pulldown resistors for enable lines to limit noise currents in these lines during transient events.
  7. Insert series pulse-proof resistors into the A and B bus lines if the TVS clamping voltage is higher than the specified maximum voltage of the transceiver bus terminals. These resistors limit the residual clamping current into the transceiver and prevent it from latching up.
  8. While pure TVS protection is sufficient for surge transients up to 1 kV, higher transients require metal-oxide varistors (MOVs) which reduce the transients to a few hundred volts of clamping voltage, and transient blocking units (TBUs) that limit transient current to less than 1 mA.