Design PCB with USB port

Hello experts,

I am designing the PCB with mini USB type B, and i placed some via under USB component to hide them like below image. However, body of USB is metal ,Is it possible to do that ?

Thank you in advance.

R9 is on the bottom layer so there is a full board between it and the usb connector body which means there should not be an issue here. (I assume you know that already but just in case)

The thing to worry about are the vias. If they are not covered by soldermask then they could get into contact with the connector housing. However, most usb connectors have enough distance between the bottom of their housing and the board for this to not be an issue. This is something we can not really check without the datasheet so you might consider posting a link to it.

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soldermask should not be used as an insulator in any case. but as you say, the important thing is to check the datasheet for keepout areas.

Hello Rene,

Again , thank you a lot because of your enthusiastic support. You help me solved many kind of issue since i started getting acquainted with KiCad :+1::+1::+1:

Sorry for my mistakes,
below link is the one that i’m using , it seems that there is no space between USB connector and board.

Hello Halachal,

Thank you !
Yes i know that, it’s not really the big issue. If possible i just want minimize the visibility of vias as less as possible for beauty purpose.

One trick (not 100% reliable!) is to add silkscreen on top of the vias. Together with mask they cover small vias pretty well.

Kapton tape is used for real insulation.

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hello eelik,

Woww, wound great ! But i wonder whether the part of the silkscreen over the vias will disappear after production or not?

Thank you.

As long as you have the board manufactured with vias “tented” the silkscreen shouldn’t be masked away from the vias. “Tenting” is the industry term for not clearing the solder mask from vias and seems to be standard now-a-days. Tenting vias or not is one of the gerber generation switches, so pay attention to that when you export to gerbers.

But, as @eelik says this trick isn’t 100% reliable. Over time with repeated connector cycles and/or vibration coming from the attached cable the silkscreen and soldermask layers may get worn away. This is why kapton tape was mentioned as it is much more abrasion resistant than silkscreen paint and soldermask emulsion.

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Hello SembazuruCDE,

Thank you a lot ! that’ exact the answer i’m looking for. :blush:

based on the datasheet, there is no keepout area, hence no need to worry about traces or vias under the connector.

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Hello Halachal,

I don’t think so, if the body of this component is not insulated, it may occur short circuit because vias are connected. Maybe that the manufacturer didn’t want to mention this information in the mechanical drawing.

That would be a dramatic oversight on their part. It looks to me like the underside is plastic:

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and again, if it WAS metal, you cannot run traces either. soldermask is not insulation.

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I have just also designed PCB with mini USB. Next to each GND pad I placed 2 vias (at both sides of pad) and wide connected them to pads. I believe this makes my connector more resistant to be rip out of board.

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The best way would be to choose a different connector. One that has the shield connection as through-hole tabs instead of as the picture shows SMT pads. I (personally) never cared for the SMT shield tab style for this very reason.

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Hello Halachal,

Thanks for your finding, i’m also not sure about the design, i think that i should buy one to try measuring it by using multimeter. Because most of real images that i found in the internet look seem that the below body is connected to GND.

Hello Piotr,

Thanks your advice, you mean that adding vias like below image to protect the pads of USB connector component out of ripping out, is it right ?

Hello Halachal,

I checked again, you’re right, i searched wrongly, the below part is plastic, :ok_hand::ok_hand:

Thank you a lot.

This is your Kapton speaking? :slight_smile:
I was going to mention that…but much depends upon whether you plan high volume manufacturing or just want to hand build a few boards. The Kapton tape will add cost.

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Hello Bobz,

Thanks for your information, he just wants to mention some tips or possible solutions. That’s fortunate for me to have more knowledge about them. In some cases, these temporary ways might be useful. :blush: