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ISO1500: Consumption when short-circuit

Arnaud DARLOT
Prodigy 40 points
Part Number: ISO1500

Dear all,

To design the power supply of the VCC2, I'm looking for the worst case consumption of the ISO1500. I think this will append when the output is short-circuited. In the datasheet, it is mentionned that IOS= +/-175mA. Following the figure 28, this is the output current measured at the output of the driver. I cannot find the maximum current on ICC2 during that specific case. Is it maximum current (ICC2 driver enabled bus loaded = 80mA) + IOS current (175mA) = 255mA ? If this is not do you have this information ?

Best regards

Arnaud

  • +1
    TI__Mastermind 49445 points

    Hi Anand,

    Thanks for reaching out and clearly stating your question.

    The current ICC2 can be expressed as the sum of driver output current (ID) and the biasing current consumed by rest of the circuit (IB). When the RS-485 but is shorted, ID is going to be the same as IOS. IB is the current excluding the driver and hence is similar to "Driver disabled, bus loaded or unloaded" which is 3.9mA max.

    Thus, ICC2(SC)(max) = ID + IB = 175mA + 3.9mA = 178.9mA.


    Regards,
    Koteshwar Rao