SLLSF31A May   2021  – December 2021 TCAN1162-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configurations and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 ESD Ratings IEC Specification
    4. 7.4 Recomended Operating Conditions
    5. 7.5 Thermal Information
    6. 7.6 Power Supply Characteristics
    7. 7.7 Electrical Characteristics
    8. 7.8 Switching Characteristics
    9. 7.9 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  VSUP Pin
      2. 9.3.2  VFLT Pin
      3. 9.3.3  Digital Inputs and Outputs
        1. 9.3.3.1 TXD Pin
        2. 9.3.3.2 RXD Pin
        3. 9.3.3.3 TS Pin
      4. 9.3.4  Digital Control and Timing
      5. 9.3.5  VIO Pin
      6. 9.3.6  GND
      7. 9.3.7  INH Pin
      8. 9.3.8  WAKE Pin
      9. 9.3.9  CAN Bus Pins
      10. 9.3.10 Local Faults
        1. 9.3.10.1 TXD Dominant Timeout (TXD DTO)
        2. 9.3.10.2 Thermal Shutdown (TSD)
        3. 9.3.10.3 Under/Over Voltage Lockout
        4. 9.3.10.4 Unpowered Devices
        5. 9.3.10.5 Floating Terminals
        6. 9.3.10.6 CAN Bus Short Circuit Current Limiting
        7. 9.3.10.7 Sleep Wake Error Timer
    4. 9.4 Device Functional Modes
      1. 9.4.1 Operating Mode Description
        1. 9.4.1.1 Normal Mode
        2. 9.4.1.2 Standby Mode
        3. 9.4.1.3 Sleep Mode
          1. 9.4.1.3.1 Remote Wake Request via Wake-Up Pattern (WUP)
          2. 9.4.1.3.2 Local Wake-Up (LWU) via WAKE Input Terminal
        4. 9.4.1.4 Fail-safe Mode
      2. 9.4.2 CAN Transceiver
        1. 9.4.2.1 CAN Transceiver Operation
        2. 9.4.2.2 CAN Transceiver Modes
          1. 9.4.2.2.1 CAN Off Mode
          2. 9.4.2.2.2 CAN Autonomous: Inactive and Active
          3. 9.4.2.2.3 CAN Active
        3. 9.4.2.3 Driver and Receiver Function Tables
        4. 9.4.2.4 CAN Bus States
  10. 10Application Information
    1. 10.1 Application Information Disclaimer
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
        1. 10.2.1.1 Bus Loading, Length and Number of Nodes
      2. 10.2.2 Detailed Design Procedures
        1. 10.2.2.1 CAN Termination
    3. 10.3 Application Curves
  11. 11Power Supply Requirements
  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 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

9.3.10.6 CAN Bus Short Circuit Current Limiting

The TCAN1162-Q1 has several protection features that limit the short circuit current during dominant and recessive when a CAN bus line is shorted. The device has TXD dominant state timeout which prevents permanently having a higher short circuit current during a dominant state fault.

During CAN communication the bus switches between the dominant and recessive states, thus the short circuit current may be viewed either as the current during each bus state or as a DC average current. The average short circuit current should be used when considering system power for the termination resistors and common mode choke. The percentage dominant is limited by the TXD dominant state timeout and CAN protocol which has forced state changes and recessive bits such as bit stuffing, control fields, and interframe space. These ensure that there is a minimum recessive time on the bus even if the data field contains a high percentage of dominant bits.

The short circuit current of the bus depends on the ratio of recessive to dominant bits and their respective short circuit currents. The average short circuit current may be calculated using Equation 2.

Equation 2. IOS(AVG) = %Transmit × [(%REC_Bits × IOS(SS)_REC) + (%DOM_Bits × IOS(SS)_DOM)] + [%Receive × IOS(SS)_REC]

Where:

  • IOS(AVG) is the average short circuit current
  • %Transmit is the percentage the node is transmitting CAN messages
  • %Receive is the percentage the node is receiving CAN messages
  • %REC_Bits is the percentage of recessive bits in the transmitted CAN messages
  • %DOM_Bits is the percentage of dominant bits in the transmitted CAN messages
  • IOS(SS)_REC is the recessive steady state short circuit current
  • IOS(SS)_DOM is the dominant steady state short circuit current

The short circuit current and possible fault cases of the network should be taken into consideration when sizing the power ratings of the termination resistance and other network components.