Ask Me Anything about Copper Weight

Events Ask Me Anything
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Join our next Ask Me Anything about copper weight where you can ask us questions on:

  • Trace width and spacing
  • Impact on impedance
  • Tradeoffs
  • And much more!

calendar icon.png Post questions before: April 30th

Please, note that this is not a live event. We ask you to post your questions on the forum before the deadline.

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I’m dropping up to 40AAC thru a board. Selectable 50Hz / 60Hz. For my protoboard I’m using 2oz copper on all 4 inner and outer layers, large planes not traces except near the fusing. I’m not a proponent of fires :slightly_smiling_face:. Standard FR4 material. All components are SMD. RoHS assembly. The components get hot, within worst-case specs, and the board is cool but for heat transfer from the hot components.

Do you recommend different approaches to this scheme? Different board material? 3oz copper on all layers? Different oz copper for different layers - say 2oz internal, 3 oz external? Or 3oz internal and 2oz external for easier assembly? What would that do to PCB cost? Manufacturability? Assembly costs - other than the Technicians will hate me. It’s small volume. Best way to attach SMD parts to the PCBA to ensure they don’t ‘melt’ off?

Thanks.

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Have you tried our current calculator tool? Kindly visit the link mentioned below and enter your values to find out the necessary conductor width for 40A. What about the number of vias used on the planes? What is the size of via used? You can also try our via current calculator tool. Apart from current, thermal management is also necessary for proper board operation, have you done the power dissipation calculations of various ICs in your board to find out if any additional heat sink is required?
https://www.protoexpress.com/tools/trace-width-and-current-capacity-calculator/
https://www.protoexpress.com/tools/via-current-capacity-temperature-rise-calculator/

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Stick with 2oz copper on all layers for your initial protoboard but focus heavily on thermal vias directly under the hot components and also consider heatsinks for the hottest components.

Also need to consider conductor width & via count as per copper thickness & current on the board. You can try our tool from our website.

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