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CAN Quiescent current

Ella Zhang
Prodigy 330 points
Other Parts Discussed in Thread: TIDA-01429

Hi Team，

I’d like to know if there will be current in the communication line of the CAN after I shut down the input.  The sample block diagram is shown on the left of the picture. The customer want a design with total Iq less than 100uA. The shut down current of the input protection device is about 50uA. We want to know how much losses are in the CAN. Could you help with this?

Best Regards,

Ella

  • 0
    TI__Guru 53575 points

    Hi Ella,

    Bus current is largely a result of the state of the bus (open, shorted, externally driven), the specific device being used, and the device's operating state. This can range from practically 0 current to several mA, even when the device is driving recessive.
    Could you provide some more information so I may supply a more precise response:

    1. What device are you planning to use in your application? Its datasheet will show leakage currents, short-circuit steady-state current, and supply currents.
    2. Will the transceiver be powered (Vcc on) in this case, or only driving recessive?
    3. What else is connected to the CAN bus? Other transceivers may draw more leakage current. How is the bus terminated?

    Regards,
    Eric

  • 0 in reply to Eric Schott1
    TI__Guru 62920 points

    Hi Ella,

    Do you still have questions about quiescent current?  If so, have you had a chance to look into Eric's clarifying questions above?  We want to make sure we understand what you are looking for so we can give the best guidance.

    Regards,
    Max

  • 0 in reply to Eric Schott1
    TI__Prodigy 330 points

    Hi Eric,

    Thanks a lot for your quick response. We don‘t have the answer for your questions. We're trying to replace the SBC to discrete solution and find the new TIDA idea. If we could reduce the leakage by the discrete solution, we could share the TIDA idea to FAEs.

    About the SBC, you could refer to TIDA-01429

    Thanks and best regards

    Ella

  • 0 in reply to Ella Zhang
    TI__Guru 53575 points

    Hi Ella,

    TICA-0429 is using the TCAN1042 CAN transceiver. This device has a Power-off bus input leakage current of 4.8uA MAX. This is when CANH = CANL = 5V and the device is unpowered Vcc = Vio = 0V. This current will be less depending on the conditions present on the bus, but this spec showcases “worst case” in semi-normal operating conditions.

    Regards,

    Eric