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ISO7740: CL(capacitive load) vs Data rate

Part Number: ISO7740

Dear Technical Support Team,

Please advice if you have CL(capacitive load) vs Data rate?

I'd like to know whether  ISO7740 drives CL > 50pF or not.

The large CL make waveform blunt in general,so the slow data rate is better.

If you have any concern about large CL , could you share it?

Best Regards,

ttd

  • ttd,

    Unfortunately we don't have any waveforms available for varying data rates and load capacitance. All we have available is the data from section 7.19 Typical Characteristics of the datasheet which only goes up to 15pF. What data rates were you wanting to analyze? What application has >50pF of load capacitance?

    Respectfully,
    Lucas

  • Hello Lucas-san,

    We will check your points.
    By the way, SLLA284B application note has information of output impedance for ISO7240. Do you have such information for ISO7740 also?
    I think time constant can be estimated with the output impedance with capacitive load. How do you think?

    Best regards,
  • FYI,

    This topic has been taken to an email conversation. The answers from the email will be posted here.

    Respectfully,

    Lucas

  • Hi ttd, Sato-san, all,

    Updates from the email conversation are as follows:

    Although the max capacitive load the ISO7740 can drive is not specified, issues aren't expected in driving loads slightly higher than 50pF. The higher load capacitance will affect rise and fall times, leading to an upper limit on max datarate that can be supported.

    Analysis is underway to check whether the ISO7740 can eliminate an issue being observed with a competitor device, and no further follow up posts are necessary.


    Thank you for your time,
    Manuel Chavez

  • Hello Manuel-san,

    Thank you for the comments.

    Best regards,