SLLSFM2A November   2024  – October 2025 TCAN2855-Q1 , TCAN2857-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  VSUP Pin
      2. 8.3.2  VCC1 Regulator
      3. 8.3.3  VCC2 Regulator
        1. 8.3.3.1 VCC2 Short to Battery Protection
      4. 8.3.4  nRST Pin
      5. 8.3.5  VEXCC Regulator
      6. 8.3.6  CAN FD Transceiver
        1. 8.3.6.1 Driver and Receiver Function
        2. 8.3.6.2 CAN Bus Biasing
      7. 8.3.7  LIN Transceiver
        1. 8.3.7.1 LIN Transmitter Characteristics
        2. 8.3.7.2 LIN Receiver Characteristics
        3. 8.3.7.3 LIN Termination
      8. 8.3.8  GND
      9. 8.3.9  LIMP Pin
      10. 8.3.10 High-side Switches (HSS1- HSS4)
      11. 8.3.11 WAKE1, WAKE2 and WAKE3/DIR Pins
        1. 8.3.11.1 WAKE Pins Alternate Configurations
          1. 8.3.11.1.1 VBAT monitoring
          2. 8.3.11.1.2 Direct Drive
      12. 8.3.12 SDO Pin
      13. 8.3.13 nCS Pin
      14. 8.3.14 SCK Pin
      15. 8.3.15 SDI Pin
      16. 8.3.16 Interrupt Function (nINT)
      17. 8.3.17 SW Pin
      18. 8.3.18 GFO Pin
    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
        3. 8.4.5.3 LIN Transceiver Faults ( TCAN2857-Q1)
      6. 8.4.6 Sleep Mode
      7. 8.4.7 Wake Functions
        1. 8.4.7.1 CAN Bus Wake Using CRXD Request (BWRR) in Sleep Mode
        2. 8.4.7.2 LIN Bus Wake
        3. 8.4.7.3 Local Wake Up (LWU) via WAKEx Input Terminal
          1. 8.4.7.3.1 Static Wake
          2. 8.4.7.3.2 Cyclic Sensing Wake
        4. 8.4.7.4 Cyclic Wake
        5. 8.4.7.5 Direct Drive in Sleep Mode
        6. 8.4.7.6 Selective Wake-up
          1. 8.4.7.6.1 Selective Wake Mode
          2. 8.4.7.6.2 Frame Detection
          3. 8.4.7.6.3 Wake-Up Frame (WUF) Validation
          4. 8.4.7.6.4 WUF ID Validation
          5. 8.4.7.6.5 WUF DLC Validation
          6. 8.4.7.6.6 WUF Data Validation
          7. 8.4.7.6.7 Frame Error Counter
          8. 8.4.7.6.8 CAN FD Frame Tolerance
          9. 8.4.7.6.9 8Mbps Filtering
      8. 8.4.8 Protection Features
        1. 8.4.8.1  Fail-safe Features
          1. 8.4.8.1.1 Sleep Mode Using Sleep Wake Error
        2. 8.4.8.2  Device Reset
        3. 8.4.8.3  Floating Terminals
        4. 8.4.8.4  TXD Dominant Time Out (DTO)
        5. 8.4.8.5  LIN Bus Stuck Dominant System Fault: False Wake Up Lockout
        6. 8.4.8.6  CAN Bus Short Circuit Current Limiting
        7. 8.4.8.7  Thermal Shutdown
        8. 8.4.8.8  Under and Over Voltage Lockout and Unpowered Device
          1. 8.4.8.8.1 Under-voltage
            1. 8.4.8.8.1.1 VSUP and VHSS Under-voltage
            2. 8.4.8.8.1.2 VCC1 Under-voltage
            3. 8.4.8.8.1.3 VCC2 and VEXCC Under-voltage
            4. 8.4.8.8.1.4 VCAN Under-voltage
          2. 8.4.8.8.2 VCC1, VCC2 and VEXCC Over-voltage
          3. 8.4.8.8.3 VCC1, VCC2 and VEXCC Short Circuit
        9. 8.4.8.9  Watchdog
          1. 8.4.8.9.1 Watchdog Error Counter and Action
          2. 8.4.8.9.2 Watchdog SPI Programming
            1. 8.4.8.9.2.1 Watchdog Configuration Registers Lock and Unlock
          3. 8.4.8.9.3 Watchdog Timing
          4. 8.4.8.9.4 Question and Answer Watchdog
            1. 8.4.8.9.4.1 WD Question and Answer Basic Information
            2. 8.4.8.9.4.2 Question and Answer Register and Settings
            3. 8.4.8.9.4.3 WD Question and Answer Value Generation
              1. 8.4.8.9.4.3.1 Answer Comparison
              2. 8.4.8.9.4.3.2 Sequence of the 2-bit Watchdog Answer Counter
            4. 8.4.8.9.4.4 Question and Answer WD Example
              1. 8.4.8.9.4.4.1 Example Configuration for Desired Behavior
              2. 8.4.8.9.4.4.2 Example of Performing a Question and Answer Sequence
        10. 8.4.8.10 Bus Fault Detection and Communication
    5. 8.5 Programming
      1. 8.5.1 SPI Communication
        1. 8.5.1.1 Cyclic Redundancy Check
        2. 8.5.1.2 Chip Select Not (nCS):
        3. 8.5.1.3 SPI Clock Input (SCK):
        4. 8.5.1.4 SPI Data Input (SDI):
        5. 8.5.1.5 SPI Data Output (SDO):
      2. 8.5.2 EEPROM
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 CAN BUS Loading, Length and Number of Nodes
      2. 9.1.2 CAN Termination
        1. 9.1.2.1 Termination
      3. 9.1.3 Channel Expansion
        1. 9.1.3.1 Channel Expansion for LIN
        2. 9.1.3.2 Channel Expansion for CAN FD
      4. 9.1.4 Device Brownout information
      5. 9.1.5 Typical Application
        1. 9.1.5.1 Design Requirements
          1. 9.1.5.1.1 LTXD Dominant State Timeout Application Note
        2. 9.1.5.2 Detailed Design Procedures
          1. 9.1.5.2.1 CAN Detailed Design Procedure
          2. 9.1.5.2.2 LIN Detailed Design Procedures
        3. 9.1.5.3 Application Curves
    2. 9.2 Power Supply Recommendations
    3. 9.3 Layout
      1. 9.3.1 Layout Guidelines
      2. 9.3.2 Layout Example
  11. 10Registers
    1. 10.1 Registers
      1. 10.1.1  DEVICE_ID_y Register (Address = 00h + formula) [reset = xxh]
      2. 10.1.2  REV_ID Register (Address = 08h) [reset = 2Xh]
      3. 10.1.3  SPI_CONFIG Register (Address = 09h) [reset = 00h]
      4. 10.1.4  CRC_CNTL Register (Address = 0Ah) [reset = 00h]
      5. 10.1.5  CRC_POLY_SET (Address = 0Bh) [reset = 00h]
      6. 10.1.6  SBC_CONFIG (Address = 0Ch) [reset = 06h]
      7. 10.1.7  VREG_CONFIG1 (Address = 0Dh) [reset = 80h]
      8. 10.1.8  SBC_CONFIG1 Register (Address = 0Eh) [reset = 01h]
      9. 10.1.9  Scratch_Pad_SPI Register (Address = 0Fh) [reset = 00h]
      10. 10.1.10 CAN_CNTRL_1 Register (Address = 10h) [reset = 04h]
      11. 10.1.11 WAKE_PIN_CONFIG1 Register (Address = 11h) [reset = 00h]
      12. 10.1.12 WAKE_PIN_CONFIG2 Register (Address = 12h) [reset = 02h]
      13. 10.1.13 WD_CONFIG_1 Register (Address = 13h) [reset = 82h]
      14. 10.1.14 WD_CONFIG_2 Register (Address = 14h) [reset = 60h]
      15. 10.1.15 WD_INPUT_TRIG Register (Address = 15h) [reset = 00h]
      16. 10.1.16 WD_RST_PULSE Register (Address = 16h) [reset = 00h]
      17. 10.1.17 FSM_CONFIG Register (Address = 17h) [reset = 00h]
      18. 10.1.18 FSM_CNTR Register (Address = 18h) [reset = 00h]
      19. 10.1.19 DEVICE_CONFIG0 Register (Address = 19h) [reset = 10h]
      20. 10.1.20 DEVICE_CONFIG1 (Address = 1Ah) [reset = 00h]
      21. 10.1.21 DEVICE_CONFIG2 (Address = 1Bh) [reset = 00h]
      22. 10.1.22 SWE_TIMER (Address = 1Ch) [reset = 28h]
      23. 10.1.23 LIN_CNTL (Address = 1Dh) [reset = 20h]
      24. 10.1.24 HSS_CNTL (Address = 1Eh) [reset = 00h]
      25. 10.1.25 PWM1_CNTL1 (Address = 1Fh) [reset = 00h]
      26. 10.1.26 PWM1_CNTL2 (Address = 20h) [reset = 00h]
      27. 10.1.27 PWM1_CNTL3 (Address = 21h) [reset = 00h]
      28. 10.1.28 PWM2_CNTL1 (Address = 22h) [reset = 00h]
      29. 10.1.29 PWM2_CNTL2 (Address = 23h) [reset = 00h]
      30. 10.1.30 PWM2_CNTL3 (Address = 24h) [reset = 00h]
      31. 10.1.31 TIMER1_CONFIG (Address = 25h) [reset = 00h]
      32. 10.1.32 TIMER2_CONFIG (Address = 26h) [reset = 00h]
      33. 10.1.33 RSRT_CNTR (Address = 28h) [reset = 40h]
      34. 10.1.34 nRST_CNTL (Address = 29h) [reset = 2Ch]
      35. 10.1.35 WAKE_PIN_CONFIG3 Register (Address = 2Ah) [reset = E0h]
      36. 10.1.36 WAKE_PIN_CONFIG4 Register (Address = 2Bh) [reset = 22h]
      37. 10.1.37 WD_QA_CONFIG Register (Address = 2Dh) [reset = 0Ah]
      38. 10.1.38 WD_QA_ANSWER Register (Address = 2Eh) [reset = 00h]
      39. 10.1.39 WD_QA_QUESTION Register (Address = 2Fh) [reset = 3Ch]
      40. 10.1.40 SW_ID1 Register (Address = 30h) [reset = 00h]
      41. 10.1.41 SW_ID2 Register (Address = 31h) [reset = 00h]
      42. 10.1.42 SW_ID3 Register (Address = 32h) [reset = 00h]
      43. 10.1.43 SW_ID4 Register (Address = 33h) [reset = 00h]
      44. 10.1.44 SW_ID_MASK1 Register (Address = 34h) [reset = 00h]
      45. 10.1.45 SW_ID_MASK2 Register (Address = 35h) [reset = 00h]
      46. 10.1.46 SW_ID_MASK3 Register (Address = 36h) [reset = 00h]
      47. 10.1.47 SW_ID_MASK4 Register (Address = 37h) [reset = 00h]
      48. 10.1.48 SW_ID_MASK_DLC Register (Address = 38h) [reset = 00h]
      49. 10.1.49 DATA_y Register (Address = 39h + formula) [reset = 00h]
      50. 10.1.50 SW_RSVD_y Register (Address = 41h + formula) [reset = 00h]
      51. 10.1.51 SW_CONFIG_1 Register (Address = 44h) [reset = 50h]
      52. 10.1.52 SW_CONFIG_2 Register (Address = 45h) [reset = 00h]
      53. 10.1.53 SW_CONFIG_3 Register (Address = 46h) [reset = 1Fh]
      54. 10.1.54 SW_CONFIG_4 Register (Address = 47h) [reset = 00h]
      55. 10.1.55 SW_CONFIG_RSVD_y Register (Address = 48h + formula) [reset = 00h]
      56. 10.1.56 HSS_CNTL2 (Address = 4Dh) [reset = 00h]
      57. 10.1.57 EEPROM_CONFIG (Address = 4Eh) [reset = 00h]
      58. 10.1.58 HSS_CNTL3 (Address = 4Fh) [reset = 00h]
      59. 10.1.59 INT_GLOBAL Register (Address = 50h) [reset = 00h]
      60. 10.1.60 INT_1 Register (Address = 51h) [reset = 00h]
      61. 10.1.61 INT_2 Register (Address = 52h) [reset = 40h]
      62. 10.1.62 INT_3 Register (Address 53h) [reset = 00h]
      63. 10.1.63 INT_CANBUS_1 Register (Address = 54h) [reset = 00h]
      64. 10.1.64 INT_7 (Address = 55h) [reset = 00h]
      65. 10.1.65 INT_EN_1 Register (Address = 56h) [reset = FFh]
      66. 10.1.66 INT_EN_2 Register (Address = 57h) [reset = 7Eh]
      67. 10.1.67 INT_EN_3 Register (Address = 58h) [reset = FEh]
      68. 10.1.68 INT_EN_CANBUS_1 Register (Address = 59h) [reset = BFh]
      69. 10.1.69 INT_4 Register (Address = 5Ah) [reset = 00h]
      70. 10.1.70 INT_6 Register (Address 5Ch) [reset = 00h]
      71. 10.1.71 INT_EN_4 Register (Address = 5Eh) [reset = DFh]
      72. 10.1.72 INT_EN_6 Register (Address = 60h) [reset = FFh]
      73. 10.1.73 INT_EN_7 Register (Address = 62) [reset = FFh]
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 CAN Transceiver Physical Layer Standards:
      2. 11.1.2 LIN Transceiver Physical Layer Standards
      3. 11.1.3 EMC Requirements:
      4. 11.1.4 Conformance Test Requirements:
      5. 11.1.5 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
    1. 13.1 Mechanical Data
8.4.8.9.4.1 WD Question and Answer Basic Information

A Question and Answer (Q&A) watchdog is a type of watchdog where instead of simply resetting the watchdog via a SPI write, the MCU must read a ‘question’ from the device, do math based on the question, and then write the computed answers back to the device. The correct answer is a 4-byte response. Each byte must be written in order, and with the correct timing to have a correct answer.

There are 2 watchdog windows, referred to as WD Response window #1 and WD Response window #2 (Figure 8-63 WD QA Windows as example). The size of each window is 50% of the total watchdog window time, tWD_RESP_WIN1 + tWD_RESP_WIN2, which is selected from the WD_TIMER and WD_PRE register bits.

Each watchdog question and answer is a full watchdog cycle. The general process is that the MCU reads the question during WD Response Window #1. The CPU must perform a mathematical function on the question, resulting in 4 bytes of answers. 3 of the 4 answer bytes must be written to the answer register within the WD Response Window #1, in correct order. The last answer must be written to the answer register after the first response window, inside of WD Response Window #2. If all 4 answer bytes are correct and in the correct order, then the response is considered good, the error counter is decremented and a new question is generated, starting the cycle over again. Once the fourth answer is written into WD Response Window #2, that window is terminated and a new WD Response Window #1 is started.

If anything is incorrect or missed, the response is considered bad and the watchdog question does NOT change. In addition, an error counter is incremented. Once this error counter exceeds the threshold (defined in the WD_ERR_CNT_SET register field), the watchdog failure action is performed. Examples of actions are an interrupt, or reset toggle, and so on.

TCAN2855-Q1 TCAN2857-Q1 WD Q&A Sequence Run
A. The MCU is not required to request the WD question. The MCU can start with correct answers, WD_ANSWER_RESP_x bytes anywhere within RESPONSE WINDOW 1. The new WD question is always generated within one system clock cycle after the final WD_ANSWER_RESP_0 answer during the previous WD Q&A sequence run.
B. The MCU can schedule other SPI commands between the WD_ANSWER_RESPx responses (even a command requesting the WD question) without any impact to the WD function as long as the WD_ANSWER_RESP_[3:1] bytes are provided within the RESPONSE WINDOW 1 and WD_ANSWER_RESP_0 is provided within the RESPONSE WINDOW 2.
Figure 8-63 WD Q&A Sequence Run