SLLSFO8C May   2024  – November 2025 TCAN2450-Q1 , TCAN2451-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  IEC ESD Ratings
    4. 6.4  Recommended Operating Conditions
    5. 6.5  Thermal Information
    6. 6.6  Supply Characteristics
    7. 6.7  Electrical Characteristics
    8. 6.8  Timing Requirements
    9. 6.9  Switching Characteristics
    10. 6.10 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  CAN FD Transceiver
        1. 8.3.1.1 Driver and Receiver Function
      2. 8.3.2  VCC1 Regulator
        1. 8.3.2.1 Functional Description of Buck Regulator
          1. 8.3.2.1.1 Fixed Frequency Peak Current Mode Control
          2. 8.3.2.1.2 Minimum ON-Time, Minimum OFF-Time, and Frequency Foldback
          3. 8.3.2.1.3 Overcurrent and Short Circuit Protection
          4. 8.3.2.1.4 Soft Start
        2. 8.3.2.2 Buck Regulator Functional Modes
          1. 8.3.2.2.1 Buck Shutdown Mode
          2. 8.3.2.2.2 Buck Active Modes
      3. 8.3.3  VCC2 Regulator
        1. 8.3.3.1 VCC2 Short to Battery Protection
      4. 8.3.4  Reset Function (nRST Pin)
      5. 8.3.5  LIMP Function
      6. 8.3.6  High Side Switches
      7. 8.3.7  WAKE and ID Inputs
        1. 8.3.7.1 ID Functionality
      8. 8.3.8  Interrupt Function (nINT Pin)
      9. 8.3.9  SPI Communication
        1. 8.3.9.1 Cyclic Redundancy Check
        2. 8.3.9.2 Chip Select Not (nCS):
        3. 8.3.9.3 SPI Clock Input (SCK):
        4. 8.3.9.4 SPI Data Input (SDI):
        5. 8.3.9.5 SPI Data Output (SDO):
      10. 8.3.10 SW Pin
      11. 8.3.11 GFO Pin
      12. 8.3.12 Wake Functions
        1. 8.3.12.1 CAN Bus Wake Using RXD Request (BWRR) in Sleep Mode
        2. 8.3.12.2 Local Wake Up (LWU) via WAKEx Input Terminal
          1. 8.3.12.2.1 Static Wake
          2. 8.3.12.2.2 Cyclic Sensing Wake
        3. 8.3.12.3 Cyclic Wake
        4. 8.3.12.4 Selective Wake-up
          1. 8.3.12.4.1 Selective Wake Mode (TCAN2451-Q1)
          2. 8.3.12.4.2 Frame Detection
          3. 8.3.12.4.3 Wake-Up Frame (WUF) Validation
          4. 8.3.12.4.4 WUF ID Validation
          5. 8.3.12.4.5 WUF DLC Validation
          6. 8.3.12.4.6 WUF Data Validation
          7. 8.3.12.4.7 Frame Error Counter
          8. 8.3.12.4.8 CAN FD Frame Tolerance
          9. 8.3.12.4.9 8Mbps Filtering
      13. 8.3.13 Protection Features
        1. 8.3.13.1 Fail-safe Features
          1. 8.3.13.1.1 Sleep Mode Through Sleep Wake Error
        2. 8.3.13.2 Device Reset
        3. 8.3.13.3 Floating Terminals
        4. 8.3.13.4 TXD Dominant Time Out (DTO)
        5. 8.3.13.5 CAN Bus Short Circuit Current Limiting
        6. 8.3.13.6 Thermal Shutdown
        7. 8.3.13.7 Under and Over Voltage Lockout and Unpowered Device
          1. 8.3.13.7.1 Under-Voltage
            1. 8.3.13.7.1.1 VSUP and VHSS Under-voltage
            2. 8.3.13.7.1.2 VCC1 Under-Voltage
            3. 8.3.13.7.1.3 VCC2 Under-voltage
            4. 8.3.13.7.1.4 VCAN Under-voltage
          2. 8.3.13.7.2 VCC1 and VCC2 Over-voltage
          3. 8.3.13.7.3 VCC1 and VCC2 Short Circuit
        8. 8.3.13.8 Watchdog
          1. 8.3.13.8.1 Watchdog Error Counter and Action
          2. 8.3.13.8.2 Watchdog SPI Programming
            1. 8.3.13.8.2.1 Watchdog Configuration Lock Mechanism
              1. 8.3.13.8.2.1.1 Watchdog Configuration in SPI Two-byte Mode
          3. 8.3.13.8.3 Watchdog Timing
          4. 8.3.13.8.4 Question and Answer Watchdog
            1. 8.3.13.8.4.1 WD Question and Answer Basic Information
            2. 8.3.13.8.4.2 Question and Answer Register and Settings
            3. 8.3.13.8.4.3 WD Question and Answer Value Generation
              1. 8.3.13.8.4.3.1 Answer Comparison
              2. 8.3.13.8.4.3.2 Sequence of the 2-bit Watchdog Answer Counter
              3. 8.3.13.8.4.3.3 Question and Answer WD Example
                1. 8.3.13.8.4.3.3.1 Example Configuration for Desired Behavior
                2. 8.3.13.8.4.3.3.2 Example of performing a question and answer sequence
        9. 8.3.13.9 Bus Fault Detection and Communication
      14. 8.3.14 Customer EEPROM Programming
    4. 8.4 Device Functional Modes
      1. 8.4.1 Init Mode
      2. 8.4.2 Normal Mode
      3. 8.4.3 Standby Mode
      4. 8.4.4 Restart Mode
      5. 8.4.5 Fail-safe Mode
        1. 8.4.5.1 SBC Faults
        2. 8.4.5.2 CAN Transceiver Faults
      6. 8.4.6 Sleep Mode
  10. 9 Device Register Tables
    1. 9.1 Device Registers
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 CAN BUS Loading, Length and Number of Nodes
      2. 10.1.2 CAN Termination
        1. 10.1.2.1 CAN Bus Biasing
      3. 10.1.3 Device Brownout Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedures
        1. 10.2.2.1 CAN Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 CAN Transceiver Physical Layer Standards:
      2. 11.1.2 EMC Requirements:
      3. 11.1.3 Conformance Test Requirements:
      4. 11.1.4 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

8.3.13.9 Bus Fault Detection and Communication

The TCAN245x-Q1 provides advanced bus fault detection. The device can determine certain fault conditions and set a status/interrupt flag so that the MCU can understand what the fault is. As with any bus architecture where termination resistors are at each end not every fault can be specified to the lowest level, meaning exact location. The fault detection circuitry is monitoring the CANH and CANL pins (currents) to determine if there is a short to battery, short to ground, short to each other or opens. From a system perspective, the location of the device also determines what can be detected. See Figure 8-47 as an example of node locations and how the ability to determine the actual fault location is impacted. Figure 8-48 through Figure 8-52 show the various bus faults based upon the three-node configuration. Table 8-23 shows what can be detected and by which device. Fault 2 is detected as no termination.

Bus fault detection is a system level situation. If the fault is occurring at the ECU, then the general communication of the bus is compromised. For complete coverage of a node, a system level diagnostic step is needed for each node and the ability to communicate this back to a central point.

TCAN2450-Q1 TCAN2451-Q1 Three Node ExampleFigure 8-47 Three Node Example
TCAN2450-Q1 TCAN2451-Q1 Open Fault 2 ExamplesFigure 8-48 Open Fault 2 Examples
TCAN2450-Q1 TCAN2451-Q1 Open Faults 3 and 4 ExamplesFigure 8-49 Open Faults 3 and 4 Examples
TCAN2450-Q1 TCAN2451-Q1 Short Faults 5 and 6 ExamplesFigure 8-50 Short Faults 5 and 6 Examples
TCAN2450-Q1 TCAN2451-Q1 Short Faults 7, 8 and 9 ExamplesFigure 8-51 Short Faults 7, 8 and 9 Examples
TCAN2450-Q1 TCAN2451-Q1 Short Faults 10 and 11 ExamplesFigure 8-52 Short Faults 10 and 11 Examples
Table 8-23 Bus Fault Pin State and Detection Table
Fault #CANHCANLFault Detected
2OpenOpenDepending upon open location the device detects this as no termination.
3OpenNormalDevice 1 detects this fault, but cannot tell the difference between it and Fault 2 and 4; Device 2 and Device 3 do not see this fault
4NormalOpenDevice 1 detects this fault but cannot tell the difference between it and Fault 2 and 3; Device 2 and Device 3 do not see this fault
5Shorted to CANLShorted to CANHYes, but not location
6Shorted to VbatNormalYes, but not location
7Shorted to GNDNormalYes, but cannot tell the difference between this and Fault 10
8NormalShorted to VbatYes, but cannot tell the difference between this and Fault 11
9NormalShorted to GNDYes, but not location
10Shorted to GNDShorted to GNDYes, but cannot tell the difference between this and Fault 7
11Shorted to VbatShorted to VbatYes, but cannot tell the difference between this and Fault 8
Table 8-24 Bus Fault Interrupt Flags Mapping to Fault Detection Number
AddressBIT(S)DEFAULTFLAGDESCRIPTIONFAULT DETECTEDACCESS
8'h5471'b0UVCAN

VCAN undervoltage interrupt

VCAN

undervoltage

R/W1C
61'b0RSVDReservedN/AR
51'b0CANHCANLCANH and CANL Shorted TogetherFault 3R/W1C
41'b0CANHBATCANH Shorted to VbatFault 6R/W1C
31'b0CANLGNDCANL Shorted to GNDFault 9R/W1C
21'b0CANBUSOPENCAN Bus Open (One of three possible places)Faults 2, 4 and 5R/W1C
11'b0CANBUSGNDCANH Shorted to GND or Both CANH & CANL Shorted to GNDFaults 7 and 10R/W1C
01'b0CANBUSBATCANL Shorted to Vbat or Both CANH & CANL Shorted to VbatFaults 8 and 11R/W1C