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TCAN1044V-Q1: Differential output slew rate

Jeffrey Chung1
Genius 3310 points

Part Number: TCAN1044V-Q1

Hi TI Team,

I want to know the differential output slew rate(V/us) of TCAN1044V-Q1. I couldn't find it, and there is no data in datasheet. Please let me know it.

[For example, 20V/us(min) to 40V/us(max), termination 60ohm and C=50pF]

Regards,

  • +1
    TI__Guru 53555 points

    Hi Jeffery,

    Differential slew rate is not a characterized parameter, so I am unable to provide any official min/max values for this behavior. However, we can infer a typical value based on available characterized parameters - differential rise/fall time and output voltage. The dominant state output voltage is specified to be between 1.5V and 3.0V under typical load. However, the timings will be recorded relative to crossing the minimum threshold of the CAN spec (we'll assume the full range for this estimation). We'll also assume a nominal recessive level of 0V. With a specified rise/fall time of 30ns and 50ns respectfully, we can estimated a typical rise time 1.5V / 30ns = 50V/us. A typical fall time estimate would be 1.5V / 50ns = 30V/us. This timing is given at R = 60-ohms, C = 100pF. 

    For what reason are you interested in this specification for this device? Typically, differential slew rate is not a critical specification because any electromagnetic noise produced by one signal is canceled by its differential pair. The more critical characteristic is generally described in rise/fall time to the levels associated with the CAN specification. 

    Let me know if you have any more questions.

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    Genius 3310 points

    Hi Eric,

    It is the requirement for CAN transceiver check sheet of my customer. I appreciate your kind calculations of typical rise and fall time. And I need to check another characterized parameter of BIT time tolerance, for example -3%(min) to 3%(max). Please check it and let me know.

    Regards,

  • 0 in reply to Jeffrey Chung1
    TI__Guru 53555 points

    Hi Jeffery,

    I understand. Thank you for the background.

    The bit timing is available at the bottom of the Switching Characteristics section under "tBIT". The tolerance percentage will depend on the data rate being used. For example, the tBIT(BUS) time at 2Mbps (500ns bit time) is between 450ns (-10%) and 530ns (+6%).

    Regards,
    Eric Schott