SLLSF17C August   2019  – October 2024 TCAN1044-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  ESD Ratings
    4. 5.4  Recommended Operating Conditions
    5. 5.5  Thermal Characteristics
    6. 5.6  Supply Characteristics
    7. 5.7  Dissipation Ratings
    8. 5.8  Electrical Characteristics
    9. 5.9  Switching Characteristics
    10. 5.10 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pin Description
        1. 7.3.1.1 TXD
        2. 7.3.1.2 GND
        3. 7.3.1.3 VCC
        4. 7.3.1.4 RXD
        5. 7.3.1.5 VIO
        6. 7.3.1.6 CANH and CANL
        7. 7.3.1.7 STB (Standby)
      2. 7.3.2 CAN Bus States
      3. 7.3.3 TXD Dominant Timeout (DTO)
      4. 7.3.4 CAN Bus Short Circuit Current Limiting
      5. 7.3.5 Thermal Shutdown (TSD)
      6. 7.3.6 Undervoltage Lockout
      7. 7.3.7 Unpowered Device
      8. 7.3.8 Floating pins
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operating Modes
      2. 7.4.2 Normal Mode
      3. 7.4.3 Standby Mode
        1. 7.4.3.1 Remote Wake Request via Wake-Up Pattern (WUP) in Standby Mode
      4. 7.4.4 Driver and Receiver Function
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 CAN Termination
      2. 8.2.2 Detailed Design Procedures
        1. 8.2.2.1 Bus Loading, Length and Number of Nodes
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.8 Floating pins

The TCAN1044-Q1 has internal pull-ups on critical pins which place the device into known states if the pin floats. This internal bias should not be relied upon by design though, especially in noisy environments, but instead should be considered a failsafe protection feature.

When a CAN controller supporting open-drain outputs is used an adequate external pull-up resistor must be chosen. This makes sure the TXD output of the CAN controller maintains acceptable bit time to the input of the CAN transceiver. See Table 7-3 for details on pin bias conditions.

Table 7-3 Pin Bias
PinPull-up or Pull-downComment
TXDPull-upWeakly biases TXD towards recessive to prevent bus blockage or TXD DTO triggering
STBPull-upWeakly biases STB towards low-power standby mode to prevent excessive system power