SLLU321 July   2022

 

  1.   TCAN1043AEVM Evaluation Module User's Guide
  2.   Trademarks
  3. 1Introduction
    1. 1.1 TCAN1043A-Q1 EVM
    2. 1.2 Applications
  4. 2Test Setup and Results
    1. 2.1 Overview and Basic Operation Settings
      1. 2.1.1 Jumper Description
      2. 2.1.2 Power Supply Inputs VSUP, VCC, and VIO
      3. 2.1.3 TXD Input
      4. 2.1.4 RXD Output
      5. 2.1.5 nSTB and EN Mode Control
      6. 2.1.6 Inhibit (INH) High Voltage Output
      7. 2.1.7 CANH and CANL Bus Pins
      8. 2.1.8 WAKE Input
      9. 2.1.9 nFAULT Output
    2. 2.2 Using CAN Bus Load, Terminations, and Protection Features
    3. 2.3 Using Customer-Installable I/O Options for Current Limiting, Pull Up and Pull Down, Noise Filtering
  5. 3EVM Setup and Basic Usage
    1. 3.1 Equipment
    2. 3.2 TCAN1043A-Q1 EVM Setup
    3. 3.3 TCAN1043A-Q1 Normal Operation 500 kbps Test Results
  6. 4Schematic and Bill of Materials
    1. 4.1 TCAN1043A-Q1 EVM Schematic
    2. 4.2 TCAN1043AEVM Bill Of Materials

2.2 Using CAN Bus Load, Terminations, and Protection Features

The TCAN1043AEVM is populated with two 120-Ω power resistors selectable via jumpers between CANH and CANL. When using one resistor, the EVM is used as a terminated end of a bus. For electrical measurements to represent the total loading of the bus, use both 120-Ω resistors in parallel to give the standard 60-Ω load for parametric measurement. The EVM also has footprints for split termination, if needed for the application. Table 2-4 summarizes how to use these termination options. If using split termination, match the resistors. Calculate the CM filter frequency using: fC = 1 / (2πRC). Normally, the split capacitance is in the range of 4.7 nF to 100 nF. Keep in mind, this is the CM filter frequency, not a differential filter that impacts the differential CAN signal directly.

Table 2-4 Bus Termination Configuration
Termination 120-Ω Resistors Split Termination Footprints
Jumper JMP3 JMP4 R9 R14 C6
No termination Open Open Not available Not available Not available
120-Ω standard termination Shorted Open
60-Ω load Shorted Shorted
Split termination Open Open 60 Ω 60 Ω 4.7 nF

The EVM also has footprints for various protection schemes to enhance robustness for extreme system-level EMC requirements. Table 2-5 summarizes these options.

Table 2-5 Protection and Filtering Configuration
Configuration Footprint Reference Use Case Population and Description
Series resistors or CM choke R7/R13 or L1
(common footprint)		 Direct CAN transceiver to bus connection R7 and R13 populated with 0 Ω (default population)
Series-resistance protection, CAN transceiver to bus connection R7 and R13 populated with MELF resistor as necessary for harsh EMC environment
CM choke (bus filter) L1 populated with CM choke to filter noise as necessary for harsh EMC environment
Bus filtering capacitors transient protection C2/C7 Bus filter Filter noise as necessary for harsh EMC environment. Use filter capacitors in combination with L1 CM choke
Transient protection C2/C7 or D1 Transient and ESD protection To add extra protection for system level transients and ESD protection, TVS diode population option via D1 footprint or varistor population via C2/C7 footprint