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SN65HVD234: ISO 11898-2 Compatible or compliant

Part Number: SN65HVD234

SN65HVD234

Hi,

I would like to know why SN64HVD234 is rated as compatible and not compliant to ISO11898-2. What are differences Compatible Vs Compliant for the SN64HVD234, 3.3V CAN device.

Thanks

  • Hi Sidat,

    The 3.3V CAN parts are designed with the ISO 11898-2 (-5) spec in mind but a 3.3V device simply cannot meet all of the requirements that are required by a 5V spec to be compliant. We try to meet every parameter that we can from the ISO 11898 spec with a 3.3V device but there are simply some that we cannot. For example here the ISO 11898-2 2016 spec specifies that CAN_H have a nominl value of 3.5V and a maximum value of 4.5V which is unacheivable in a 3.3V design.

    This is why a device can be compatible but now compliant. Please let me know what other questions you have?

  • Hi Michael:
    The Min CanH (2.45V) can't meet the demand of ISO 11898-2 's 2.75V standard.
    How to understand the description in datasheet"Compatible With ISO 11898-2" ?
    Can SN65HVD234-Q1 be used in automotive application?
  • Hi Henry,

    ISO 11898-2 was developed for 5V automotive systems and does not include any 3.3V requirements. When we say "compatible with ISO 11898-2" we are saying that the 3.3V part(s) are designed to meet as many of the ISO specs as possible but there are some that we simply cannot meet due to the 3.3V supply. For example Vcm in CAN is typically Vcc/2 or 2.5 for 5V CAN but with 3.3V CAN devices this is hard to due. You can see the typical recessive level for the SN65HVD234-Q1 is 2.3V so we "try" to meet all of the specs.

    There are some OEMs that have discrete 3.3V networks in their communication hierarchies and require this 3.3V Q1 devices which is why we have it. The SN65HVD234-Q1 has a full automotive CAN qualification just like any other Q1 part from TI.

    Please let me know if you have any more questions?

  • Hi Michael:
    Thanks for your reply, I got the situation now. But I still concern if the different range of CanH will have interference with other 5.0V Can device?
    I will use 5.0V CAN and 3.3V CAN in the same bus .
  • Hi Henry,

    5V and 3.3V CAN are interoperable so no issue there. The requirements to meet CAN bus levels are >=500mV is a recessive level and >=900mV is a dominant. 3.3V and 5V CAN both meet these requirements. The problem in mixing in mixing the two technologies is the common mode levels or recessive levels will be different which can lead to increased levels of emissions.

    Please let me know if you have any more questions?