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TCAN1042H: schematic double check

Wesley Huang
Expert 1030 points
Part Number: TCAN1042H
Hi team，

Could you please help me double check with this schematic?
 1. The RS is the S pin. The VREF is NC pin. The D is TXD pin. The R is RXD pin.  

 

Best Regards

Wesley Huang

  • 0
    TI__Mastermind 47895 points

    Hi Wesley,

    Overall the schematic looks good. See my comments and recommendations below. 

    • Decoupling capacitor valued well (C34). Ensure this is placed close to the IC.
    • Series resistors on digital lines are acceptable. 
    • Pin 5 (NC) floating is fine.
    • 3.3V pull-up on STB is alright.
      • Vih for pin is 2.0V.
      • When signal CAN_H_RS is high-z, transceiver will be in standby mode.
    • Note that RXD will output Voh of 4.6V typical. Make sure processor can handle this. If not, please consider use of 'V' variant. 
    • Termination included and valued well.
    • Bus capacitor (footprint), PTC, and TVS diodes included. Place close to board connectors.
    • Series resistors may cause issue in longer networks.
      • The differential nature of CAN signals don't do well with large series resistances. Placed resistors will further attenuate differential signals that are already decreased in magnitude from cable resistances. With other protection in place, CAN transceivers are typically able to withstand transient events without series resistor protection.

    Let me know if you have any questions or particular concerns regarding my comments or the design. 

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    Expert 1030 points

    Hi Eric,

    Thanks for your perfect answer. Appreciate that!

     1. Can I remove the series resistors?  What's the benefit of the series resistors?

     2. what's the suggested range of the Series resistors？

    Best Regards

    Wesley Huang

     

  • 0 in reply to Wesley Huang
    TI__Mastermind 47895 points

    Hi Wesley,

    I would recommend removing the series resistors. The benefit of these would be limiting the current through the CAN lines during a fault event. However, the PTC fuses already accomplish this.

    Regards,
    Eric Schott