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I plan to use a MTU1D0509MC Series isolated DC-DC converter to power an in-amp and supply bias current for a resistive sensor. I couldn't find anything in the datasheet about asymmetric loading: Datasheet

The supply is rated for 1W and I need about 40mA from +9 to ground (360mW), and less than 1mA from the - rail. Cause any issues? I really don't want to introduce any unnecessary noise.

griffin175
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  • Depends on the implementation. Have to tried to ask the manufacturer? Most probably no issues. – winny Nov 08 '21 at 09:37
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    Could you please put a schematic/diagram of your implementation? How will you split the isolated 9V output and determine the common point? – Rohat Kılıç Nov 08 '21 at 11:15
  • Which "- rail" ? Your text mentions it, but the MTU1S0509MC doesn't have any (assuming you connect the negative output to ground as per your question). – tobalt Nov 08 '21 at 11:31
  • @RohatKılıç If you look at the datasheet, you will see there is a +9v output, -9v output, and a ground. The common point is predetermined by the component. – griffin175 Nov 08 '21 at 14:22
  • You probably have been led to a misunderstanding by the diagram at p.8. The product you are planning to use (MTU1S0509MC) has only one output i.e. there's no symmetrical output whatsoever. – Rohat Kılıç Nov 08 '21 at 14:26
  • @RohatKılıç oops, looks like I copied the wrong part number. I meant MTU1*D*0509MC – griffin175 Nov 08 '21 at 22:46
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    In this case, it is fine to draw asymmetric currents from the pos and neg rails. Check the datasheet carefully if it mentions a minimum current to stay in regulation. It might be, that you have to add something else to the negative rail (like a LED or dummy resistor) to reach this minimum load if needed. – tobalt Nov 09 '21 at 04:47
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    Looking at the load regulation graphs given at p.6, I'd expect them to have their both outputs regulated tightly enough even if they are loaded asymmetrically. – Rohat Kılıç Nov 09 '21 at 11:41

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