ZHCSNF0B May   2018  – October 2021 ISOW1412 , ISOW1432

PRODMIX  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 说明（续）
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1  Absolute Maximum Ratings
    2. 8.2  Recommended Operating Conditions
    3. 8.3  Thermal Information
    4. 8.4  Power Ratings
    5. 8.5  Insulation Specifications
    6. 8.6  Safety-Related Certifications
    7. 8.7  Safety Limiting Values
    8. 8.8  Electrical Characteristics
    9. 8.9  Supply Current Characteristics at VISOOUT = 3.3 V
    10. 8.10 Supply Current Characteristics at  VISOOUT = 5 V
    11. 8.11 Switching Characteristics at VISOOUT = 3.3 V
    12. 8.12 Switching Characteristics at VISOOUT = 5 V
    13. 8.13 Insulation Characteristics Curves
    14. 8.14 Typical Characteristics
  9. 9 Parameter Measurement Information
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Power Isolation
    3. 10.3 Signal Isolation
    4. 10.4 RS-485
    5. 10.5 Functional Block Diagram
    6. 10.6 Feature Description
      1. 10.6.1 Power-Up and Power-Down Behavior
      2. 10.6.2 Protection Features
      3. 10.6.3 Failsafe Receiver
      4. 10.6.4 Glitch-Free Power Up and Power Down
    7. 10.7 Device Functional Modes
    8. 10.8 Device I/O Schematics
  11. 11Application and Implementation
    1. 11.1 Application Information
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
        1. 11.2.2.1 Data Rate, Bus Length and Bus Loading
        2. 11.2.2.2 Stub Length
        3. 11.2.2.3 Insulation Lifetime
  12. 12Power Supply Recommendations
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
  14. 14Device and Documentation Support
    1. 14.1 Documentation Support
      1. 14.1.1 Related Documentation
    2. 14.2 Receiving Notification of Documentation Updates
    3. 14.3 支持资源
    4. 14.4 Trademarks
    5. 14.5 Electrostatic Discharge Caution
    6. 14.6 术语表
  15. 15Mechanical, Packaging, and Orderable Information

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10.6.2 Protection Features

The ISOW14x2 family of devices has multiple protection features to create a robust system level solution.

  • The first feature is an Enable/Fault protection feature. This EN/FLT pin can be used as either an input pin to enable or disable the integrated DC-DC power converter or as an output pin which works as an alert signal if the power converter is not operating properly. In the /Fault use case, a fault is reported if VDD > 7 V, VDD < 2.5 V, or if the junction temperature >170°C. When a fault is detected, this pin will go low, disabling the DC-DC converter to prevent any damage.
GUID-20211018-SS0I-RFBM-BB9H-G3GBJPJSVPNR-low.gif Figure 10-3 EN Fault Pin Diagram

  • An over-voltage clamp feature is present on VISOOUT which will clamp the voltage at 6 V at Profibus mode (MODE = VISOOUT ) or 4V at RS485 mode (MODE = GND2), if there is an increase in voltage seen. For device reliability, it is recommended that VISOOUT stays lower than the over-clamp voltage for device reliability.

  • Over-Voltage Lock Out (OVLO) on VDD will occur when a voltage higher than 7 V on VDD is seen. At OVLO, the device will go into a low power state and the EN/FLT pin will go low.

  • These devices are protected against output overload and short circuit. In cases of overload or short on power converter output VISOOUT, maximum duty cycle of power converter is limited. In cases of driver bus short circuit due to the external power supply cable shorting to the bus cable, or due to bus contention, short circuit current protection on RS-485 chip restricts the bus current to ±250 mA maximum.
  • Thermal protection is also integrated to help prevent the device from getting damaged under such scenarios. An increase in the die temperature is monitored and the device is disabled when the die temperature becomes 165℃ (typical), thus disabling the short condition. The device is re-enabled when the junction temperature becomes 155℃ (typical). If an overload or output short-circuit condition prevails, this protection cycle is repeated. Care should be taken in the system design to prevent repeated or prolonged exposure to bus shorts as this exposes the device to high junction temperatures for extreme amounts of time affecting device reliability.