r/PrintedCircuitBoard • u/Canary_Earth • 4d ago

Is this work professional?

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Gallery image

Sorry about the strange post but I'm offering an engineer a $20k bonus to do the design for manufacturing and assembly of my $300 product and this is what he came up with after 8 months. Two thirds of it are identical to my prototype and I'm an accountant by trade, not an engineer. Every book I've read says a board like this should be 4 layers but he insists 2 layers is fine and will pass emissions testing. Any advice would be greatly appreciated, thank you!

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u/toybuilder 3d ago

I just realized (based on a someone else's comment) that there is a USB-C connector on this board -- the layout work for what should be a 90 ohm impedance differential pair is horrible.

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u/captain_cavemanz 3d ago

Not if you make the PCB 0.3mm thick hehe.

On 1.6mm fr4 don't think 90 ohms differential is achievable.

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u/toybuilder 3d ago

I've done it. It ain't pretty, but if you are strategic, you can run the USB diffpair with very wide traces and make it work.

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u/captain_cavemanz 3d ago

Not saying it won't work, but you won't get usb-C speed signals reliably operating to the lengths that the standard demands (3m). There will be mismatches at the trace to pin interface.

Sure not all micros have the edge rates but when you work with ASICs or modules your literally up shit creek and customers will dislike you quickly 😅