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I am using D050505S-1WR3 in my design for powering an isolated CAN transceiver. The can transceiver is the ISO1042BDWV from TI.

Below is the schematic of the power supply and CAN transceiver.

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enter image description here

During the review I received a comment like we need to connect a resistor in parallel with the capacitor (C518) ie at the output. Why? The minimum output current of isolated power module is 10 mA.

As per my understanding the resistor is not required because the CAN transceiver is acting as a load.

The current consumption of the CAN transceiver is given below.

enter image description here

  • Do I need to connect a resistor at the output of an isolated DC-DC converter?
  • May I know your comments about the isolated DC-DC converter schematic?
  • Do I need to take any precautions in the layout of isolated DC-DC converter?
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  • \$\begingroup\$ 2.8 mA is less than 10 mA. And, who's to say that other modes don't produce even lower load currents. \$\endgroup\$
    – Andy aka
    Commented Oct 11, 2023 at 12:20
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    \$\begingroup\$ You can call it any name you choose to. \$\endgroup\$
    – Andy aka
    Commented Oct 11, 2023 at 12:35
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    \$\begingroup\$ We can't see the whole chart, but that looks like nominal and maximum current. No minimum. And, as Andy said even the stated value is lower than 10mA. Just put a resistor in there. \$\endgroup\$
    – Drew
    Commented Oct 11, 2023 at 16:29

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Do I need to connect a resistor at the output of Isolated DC-DC converter?

Simple answer, yes. You have a digital load with out a published minimum current draw. If you ignore this, you're just asking for subtle problems down the road.

May I know your comments about isolated DC-DC converter schematic?

Looks pretty standard. It should be fine if you followed the recommendations from the datasheet. I'd loose the pi filter unless you know you need it. Inductive filters can cause problems just as easily as they can solve them.

Do I need to take any precautions in the layout of isolated DC-DC converter?

Not really. It's self contained. However it is good practice to make sure those bypass caps are near the device pins.

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  • \$\begingroup\$ Thank you.I will connect a 500 ohm so that 10mA will be take always.May I know your thoughts. \$\endgroup\$
    – Confused
    Commented Oct 12, 2023 at 4:48

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