SLLSFN9 October   2021 TCAN1044AEV-Q1

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  ESD Ratings
    3. 6.3  ESD Ratings - IEC Specifications
    4. 6.4  Recommended Operating Conditions
    5. 6.5  Thermal Characteristics
    6. 6.6  Supply Characteristics
    7. 6.7  Dissipation Ratings
    8. 6.8  Electrical Characteristics
    9. 6.9  Switching Characteristics
    10. 6.10 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 Pin Description
        1. 8.3.1.1 TXD
        2. 8.3.1.2 GND
        3. 8.3.1.3 VCC
        4. 8.3.1.4 RXD
        5. 8.3.1.5 VIO
        6. 8.3.1.6 CANH and CANL
        7. 8.3.1.7 STB (Standby)
      2. 8.3.2 CAN Bus States
      3. 8.3.3 TXD Dominant Timeout (DTO)
      4. 8.3.4 CAN Bus Short-Circuit Current Limiting
      5. 8.3.5 Thermal Shutdown (TSD)
      6. 8.3.6 Undervoltage Lockout
      7. 8.3.7 Unpowered Device
      8. 8.3.8 Floating pins
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operating Modes
      2. 8.4.2 Normal Mode
      3. 8.4.3 Standby Mode
        1. 8.4.3.1 Remote Wake Request via Wake-Up Pattern (WUP) in Standby Mode
      4. 8.4.4 Driver and Receiver Function
  9. 9 Application Information Disclaimer
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 CAN Termination
      2. 9.2.2 Detailed Design Procedures
        1. 9.2.2.1 Bus Loading, Length and Number of Nodes
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.3 TXD Dominant Timeout (DTO)

During normal mode, the only mode where the CAN driver is active, the TXD DTO circuit prevents the local node from blocking network communication in the event of a hardware or software failure where TXD is held dominant longer than the timeout period tTXD_DTO. The TXD DTO circuit is triggered by a falling edge on TXD. If no rising edge is seen before the timeout period of the circuit, tTXD_DTO, the CAN driver is disabled. This frees the bus for communication between other nodes on the network. The CAN driver is reactivated when a recessive signal is seen on the TXD pin, thus clearing the dominant time out. The receiver remains active and biased to VCC/2 and the RXD output reflects the activity on the CAN bus during the TXD DTO fault.

The minimum dominant TXD time allowed by the TXD DTO circuit limits the minimum possible transmitted data rate of the device. The CAN protocol allows a maximum of eleven successive dominant bits (on TXD) for the worst case, where five successive dominant bits are followed immediately by an error frame. The minimum transmitted data rate may be calculated using Equation 1.

Equation 1. Minimum Data Rate = 11 bits / tTXD_DTO = 11 bits / 1.2 ms = 9.2 kbps
GUID-0C4BBECE-72AE-429F-8121-21390898265B-low.gifFigure 8-4 Example Timing Diagram for TXD Dominant Timeout