• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 15 subscribers
  • Views 273 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ISO7742-Q1: ISO7742-Q1 Questions

Xing He
Intellectual 2025 points
Part Number: ISO7742-Q1
Other Parts Discussed in Thread: ISO7742

Hi Team,

My customer is using ISO7742F-Q1. For ISO7742F-Q1, Do you have more detailed information of IIH, IIL.

What is the min, typ value of IIH.

What is the max, typ value of IIL.

What is the max, typ value of IIL., IIH. at other input voltage?

 

       Another question, if input pin is open. Then how can the output to keep low? Because the leakage current maybe -10uA from the above table. For example, if assume the input resistance 250kohm. Then 10uA*250kohm=2.5V. This is not a certain input. So the output will be undetermined?

 

       Thanks.

  • 0
    TI__Mastermind 49445 points

    Hi Xing,

    Thanks for reaching out.

    Regarding IIH and IIL, ISO7742 inputs are CMOS inputs having very high input impedance and hence the current is going to be a lot less than 10µA. But there are input pull-up / pull-down resistors that could contribute a few µA of current (<10µA).

    Since these currents are so small (1000 times smaller) and insignificant compared to device overall power consumption, minimum and typical current values for inputs pins is not going to be of any importance. Hence, we do not characterize device for min and typical currents and instead quote worst-case value.
    Please do let me know if there is any specific reason or concern why customer is worried about this current.

    Regarding your other question on input pin floating condition, please note that 10µA is not the actual input current but is the worst-case current that might go into input pin. The actual current will depend on the actual input voltage applied.

    If input pin is floating, then IIH or IIL will be 0µA as there is no current flowing into or out of input pin. Since there is internal pull-down for ISO7742F, input pin will be held close to 0V as there is voltage applied to the pin. Thus, the output will go to LOW state as stated in the Function Table of datasheet.

    I hope this clarifies your doubts, thanks.



    Regards,
    Koteshwar Rao