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TCAN1042V-Q1: TCAN1042V-Q1 and TCAN1044V-Q1 application issue

Part Number: TCAN1042V-Q1
Other Parts Discussed in Thread: TCAN1044V, TCAN1043

Dear TI:

  Please help to check TCAN1042V and TCAN1044V application issue:

1, Can TCAN1042V/1044V power supply by DC-DC, What are the requirements for ripple?

2, In sleep mode, Can TCAN support turn off the VCC 5V supply, only keep the 3.3V  VIO power supply?  And Whether wake-up is supported under such conditions?

3, Can TCAN1042/1044 support no chock and ESD TVS design? 

Thanks!

Regards 

Eric Shen

  • Hi Eric,

    See my feedback below:

    1. A DC/DC supply can certainly be used for VCC.  There is no hard limit on ripple requirements, as long as the output voltage of the DC/DC keeps VCC within 10% of 5V (4.5-5.5V).  However, there will be an inverse relationship between ripple voltage and EMC performance on the CAN bus.  Ripple on VCC will couple through the CAN driver to negatively affect the EMC performance of the CAN bus.  There is no hard limit, but be aware that the better the ripple, the better electromagnetic capability you will see.

    2. The TCAN1042 and TCAN1044 devices do not support Sleep Mode.  Do you mean Standby Mode?  In Standby Mode, wake up is supported through Wake-Up-Pattern on the CAN bus, but VCC and VIO must remain active during Standby Mode.  If you would like to support Sleep Mode (and allow VCC and/or VIO to turn off), then I would suggest that you consider the TCAN1043 device.

    3. The TCAN1042 device can meet automotive Classic CAN data rates with excellent EMC performance without the use of a choke.  However, if you application is automotive, then you will mostly likely want a choke for the TCAN1044 or for CAN FD data rates (1Mbps-5Mbps) in order to filter out common-mode electromagnetic emissions.

    The TCAN1042 is rated for 15kV of IEC ESD, and 16kV of HBM ESD (Human Body Model).  

    The TCAN1044 is also being designed to target 15kV of IEC ESD.  

    If the ESD requirements in your application exceed these limits, then you will require TVS diodes for your application.  Otherwise, these devices should operate on their own.

    Best Regards,

    Max Megee

    TI Transceiver Applications

  • Hi Max:

          Thanks for your reply, I need check with you again about the standby mode:
          Your reply : "In Standby Mode, wake up is supported through Wake-Up-Pattern on the CAN bus, but VCC and VIO must remain active during Standby Mode.  "

           I found from datasheet as below, it seems like a contradiction, please help to check again. Thanks!

  • Eric,

    You are correct; that was my mistake.  Standby Mode relies on the low-power receiver only, which is solely supplied by VIO.  So you may power down VCC and operate functionally in Standby Mode.

    Do you have any other questions on TCAN1042 and TCAN1044?

    Thanks,

    Max

  • Hi  Max:
        OK, Thanks!

    Regards!

    Eric