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ISO7340-Q1: What is the maximum current consumption on side2 with 3.3V Supply

Sudheer Sai4
Prodigy 150 points
Part Number: ISO7340-Q1

Hi 

We are using ISO7340-Q1 in our design. We would like to know the maximum current consumed from the side 2 (output) of the device when powered with 3.3V. The maximum signal frequency for the application is 20kHz.

As per the datasheet (Sec 7.12) the maximum current consumed at the output supply (3.3V) is 3.6mA. Is this correct?

Is there any other specification that i am missing which will cause the current consumed on side2 of this device more than 3.6mA?

The current consumption is a critical for our application. Please let us know if there is any other possibility that this device will consume more than 3.6mA on side2.

Thanks 

Sudheer

  • 0
    Guru 243090 points
    Yes, 3.6 mA is correct for any speed less than 1 Mbit/s (any frequency less than 500 kHz).

    This measurement assumes that each output drives a CMOS input with not DC input current, and that the combined capacitance of the signal line and that input are 15 pF. If you have a DC current (e.g., through a pull-up/-down resistor), or if the capacitance is higher (e.g., the gate of a power MOSFET), then those additional loads must be driven by the ISO7340 and increase its current consumption.
  • 0 in reply to Clemens Ladisch
    Prodigy 150 points

    Hi Thanks for the clarification.

    This resolved my ambiguity about the current consumption.

    One more query is on the power rating given in the section 7.5. I feel the values given in this tabel from section 7.5 (for ex 68mW -> Max Power dissipation by side 2 of ISO7340-Q1) is the maximum power dissipation supported by this IC and not the actual power dissipated. Because this at 3.3 V, 68mW corresponds to 20.6mA.

    This 20.6mA value is contradictory to the 3.6mA value given in the section 7.12.

  • 0 in reply to Sudheer Sai4
    Guru 243090 points

    Yes, the power ratings are maximum allowed values.