How to Use can bus transceiver TJA1051T/3: Examples, Pinouts, and Specs

The TJA1051T/3 is a high-speed CAN (Controller Area Network) transceiver designed to facilitate reliable communication in automotive and industrial environments. Acting as an interface between a CAN controller and the physical CAN bus, this component ensures robust data transmission with low electromagnetic interference (EMI) and high noise immunity. It supports data rates of up to 1 Mbps, making it suitable for modern high-speed CAN networks.

• Automotive systems (e.g., engine control units, body control modules)
• Industrial automation and control systems
• Robotics and embedded systems
• Electric vehicle (EV) battery management systems
• Building automation and HVAC systems

• Supply Voltage (Vcc): 4.5 V to 5.5 V
• Data Rate: Up to 1 Mbps
• Bus Voltage Range: -27 V to +40 V
• Standby Current: < 10 µA (in standby mode)
• Operating Temperature Range: -40°C to +125°C
• Electromagnetic Compatibility (EMC): Low EMI and high ESD protection
• ESD Protection: ±8 kV (HBM) on bus pins
• Package Type: SO8 (Small Outline Package with 8 pins)

The TJA1051T/3 is an 8-pin device. Below is the pinout and description:

1. Power Supply:

   • Connect the VCC pin to a regulated 5 V power supply.
   • Connect the GND pin to the system ground.
   • If using 3.3 V logic levels, connect the VIO pin to a 3.3 V supply.

2. CAN Bus Connection:

   • Connect the CANH and CANL pins to the corresponding lines of the CAN bus.
   • Use a 120-ohm termination resistor between CANH and CANL at each end of the bus.

3. Controller Interface:

   • Connect the TXD pin to the CAN controller's TXD output.
   • Connect the RXD pin to the CAN controller's RXD input.

4. Standby Mode:

   • To enable normal operation, pull the STB pin low.
   • To enter standby mode (low-power mode), pull the STB pin high.

• Ensure proper decoupling by placing a 100 nF ceramic capacitor close to the VCC pin.
• Use twisted-pair cables for the CANH and CANL lines to minimize noise and EMI.
• Verify that the CAN bus is properly terminated with 120-ohm resistors at both ends.
• Avoid exceeding the maximum voltage ratings on any pin to prevent damage to the transceiver.

Below is an example of how to connect the TJA1051T/3 to an Arduino UNO for basic CAN communication:

• TJA1051T/3 TXD → Arduino UNO Digital Pin 2
• TJA1051T/3 RXD → Arduino UNO Digital Pin 3
• TJA1051T/3 VCC → Arduino UNO 5V
• TJA1051T/3 GND → Arduino UNO GND
• TJA1051T/3 CANH → CAN Bus High Line
• TJA1051T/3 CANL → CAN Bus Low Line
• TJA1051T/3 STB → Arduino UNO Digital Pin 4 (for standby control)

#include <SPI.h>
#include <mcp_can.h> // Include the MCP_CAN library for CAN communication

// Define CAN transceiver pins
#define CAN_CS 10 // Chip Select pin for the CAN controller
#define STB_PIN 4 // Standby control pin for the TJA1051T/3

MCP_CAN CAN(CAN_CS); // Create an instance of the MCP_CAN class

void setup() {
  pinMode(STB_PIN, OUTPUT);
  digitalWrite(STB_PIN, LOW); // Set TJA1051T/3 to normal mode

  Serial.begin(115200);
  while (!Serial);

  // Initialize the CAN controller at 500 kbps
  if (CAN.begin(MCP_ANY, CAN_500KBPS, MCP_8MHZ) == CAN_OK) {
    Serial.println("CAN initialized successfully!");
  } else {
    Serial.println("CAN initialization failed!");
    while (1);
  }
  CAN.setMode(MCP_NORMAL); // Set CAN controller to normal mode
}

void loop() {
  // Send a test message
  byte data[8] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
  if (CAN.sendMsgBuf(0x100, 0, 8, data) == CAN_OK) {
    Serial.println("Message sent successfully!");
  } else {
    Serial.println("Message sending failed!");
  }
  delay(1000); // Wait 1 second before sending the next message
}

1. No Communication on the CAN Bus:

   • Ensure the CANH and CANL lines are properly connected and terminated with 120-ohm resistors.
   • Verify that the STB pin is pulled low for normal operation.
   • Check the power supply voltage on the VCC and VIO pins.

2. High Noise or EMI on the Bus:

   • Use twisted-pair cables for the CANH and CANL lines.
   • Add decoupling capacitors near the power supply pins.

3. Arduino Fails to Initialize CAN Communication:

   • Ensure the MCP_CAN library is installed and configured correctly.
   • Verify the SPI connections between the Arduino and the CAN controller.

4. Overheating of the Transceiver:

   • Check for short circuits on the CANH and CANL lines.
   • Ensure the bus voltage does not exceed the specified range (-27 V to +40 V).

Q1: Can the TJA1051T/3 operate with 3.3 V logic levels?
A1: Yes, the TJA1051T/3 supports 3.3 V logic levels when the VIO pin is connected to a 3.3 V supply.

Q2: What is the maximum cable length for the CAN bus?
A2: The maximum cable length depends on the data rate. For 1 Mbps, the maximum length is approximately 40 meters. For lower data rates, longer cable lengths are possible.

Q3: Is the TJA1051T/3 compatible with older CAN standards?
A3: Yes, the TJA1051T/3 is fully compatible with ISO 11898-2 and ISO 11898-5 standards.

Q4: Can I use the TJA1051T/3 in a multi-node CAN network?
A4: Yes, the TJA1051T/3 is designed for multi-node CAN networks and supports up to 120 nodes.