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TCAN1145-Q1: Split termination resistor and cap recommendation

Irene Qin
Expert 3355 points
Part Number: TCAN1145-Q1

Hi team

This is FAE irene, one of my EV/HEV's end customer required when TCAN1145 without termination resistor, there should be split termination resistor (normally from what I seen is two 1.3kohm )added as below:

My I ask does TCAN1145 has recommendation about this split resistor and capacitor value? Is there any equation that customer could follow?

Thanks

irene

  • 0
    TI__Guru 74262 points

    Irene,

    One of our engineers will get back to you at the end of the day 01/19/2024.

    Regards,

    Eric Hackett 

  • 0 in reply to Eric Hackett
    TI__Expert 3355 points

    Hi Eric

    Add one question as below:

    "The differential input resistance of the TCAN114x-Q1 is a minimum of 30 kΩ."

    What is limiting this resistance to 30kohm? Is the current driven capability of TCAN1145-Q1?

  • +1 in reply to Irene Qin
    TI__Mastermind 28030 points

    Hi Irene,

    I would recommend to use two 60 Ohm resistors on each split termination and 100 nF filtering capacitor.

    There's no a specific equation but by the CAN standard we need to make sure that all termination resistance above 55 ohms. You can either use a single 120 Ohm or two 60 Ohm as split terminations. For the capacitance the common range will be 4.7nF to 100nF. This capacitor is meant to work the split termination resistors configuration be low-pass filters for both CANH and CANL.

    Regarding your second question, I think it was a design specification to meet the 1.5 V requirement with a 50 Ω load, please find section 11.2.1 in datasheet.

    Regards,

    Sean