SLLA636 June   2024 TCAN3403-Q1 , TCAN3404-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 25V CAN Transceiver
  6. 3TI's TCAN3403-Q1, TCAN3404-Q1 3.3V CAN FD Transceivers
  7. 4 Interoperability (IOPT) of TCAN340x-Q1
  8. 5 EMC of TCAN340x-Q1
  9. 6 Benefits of TCAN340x-Q1 over competition 3.3V CAN offerings
  10. 7 Conclusion

2 5V CAN Transceiver

As seen from the functional block diagram of 5V CAN transceiver below, for the driver to be able to produce minimum differential voltage of 1.5V across CANH-CANL terminals, high side and low side transistors (highlighted in dotted red rectangle in Figure 2-1) have to be sized appropriately so that maximum drop across them is 3V when operating from 4.5V supply (since main 5V supply can vary by ±10%).

CAN Transceiver Block Diagram Figure 2-1 CAN Transceiver Block Diagram

Correspondingly the specifications for CANH and CANL with respect to GND are specified in the physical layer standard as shown in Table 2-1.

Table 2-1 5V CAN Transceiver Specifications
Parameter Conditions Min (V) Max (V)
VCANH Dominant output, Bus load 50 Ω ≤ RL ≤ 65 Ω 2.75 4.5
VCANL 0.5 2.25

The CAN bus transceiver can be the only 5V component in the sub-system. With the modern MCU’s I/O supply going down to 3.3V, there is a possibility to eliminate the 5V rail altogether resulting in power stage simplification and cost saving by BOM reduction and PCB space reduction.

A high bus-fault tolerant CAN bus transceiver that is footprint compatible to standard 5V CAN transceivers, and that operates from a single 3.3V supply can help simplify the design and reduce cost by eliminating the need for a dedicated 5V supply.