PCB prototype supplier meeting nRF52840 via-in-pad requirements

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Mon, 03 Aug 2020 05:40:55 GMT

Oh no. The center pad ground vias are a must ! It's only about via-in-pad in the pad ring.

Ah, and check also this document: http://infocenter.nordicsemi.com/pdf/nan_040.pdf

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Radio — Sun, 02 Aug 2020 06:56:12 GMT

Hi Beat/Simonr,

Thanks for the information. One quick question.

When you mentioned via-in-pad, did you also mean, ground vias which is just underneath the aQFN73 package pad?

Thanks!

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Simonr — Wed, 29 Jul 2020 08:44:19 GMT

I just wanted to confirm that Beat is absolutely correct. Using these other vias should not cause any performance issues.

Best regards,

Simon

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Tue, 28 Jul 2020 13:17:31 GMT

No, to my knowledge no performance issue at all.

You just have only 26 GPIOs to use instead of 48. Should be no problem for a small design.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Radio — Tue, 28 Jul 2020 08:53:40 GMT

Hi Beat,

Many thanks for the reply. My design is something similar to a nRF52840 dongle. Its a small design. I am not going to have GPIO on the inner pad row. Will using other Via types affects my performance?

Thanks a lot!

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Tue, 28 Jul 2020 08:19:14 GMT

We usually use Eurocircuits or Multi-CB for prototype manufacturing. Often Multi-CB is cheaper.

However, for the nRF52840 we used Eurocircuits, because they were able to produce via-in-pad. This feature is only required if you are going to use any GPIO on the inner pad row. If you stick to the outer pad row, then you may use any other PCB manufacturer.

If you wanna use the inner pad row for GPIOs and thus via-in-pads, then ask for a quote with special via requirements. In your Gerber data you should add a mechanical layer which marks the special via-in-pads.

And yes, Eurocircuits does PCBA, but we never used this service. So I haven't got experience here with Eurocircuits.

Hope, I could help.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Radio — Tue, 28 Jul 2020 08:07:39 GMT

Hi Beat,

I am trying to fabricate a PCB/PCBA for the first time and looking for a recommended manufacture. I am not planning to do any production level manufacturing. Just for prototyping.

I would like to know your experience with Eurocircuits if I am going to design a PCB based on nRF52840. Or any other manufacture you have tried with?

Do they also do PCBA?

How about the cost (e.g. a PCB with dimension 4cm x 4 cm)?

Thanks a lot.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Wed, 30 Jan 2019 07:54:06 GMT

Thanks for your hint about HDI and microvias...

However, it seems that it's not as simple as that:

Würth clearly offers HDI capabilities, but they stated by Email, that they cannot do this small size of via-in-pad.

On the other hand Eurocircuits will do the job, but they do not mention HDI nor microvias on their website.

However, I found a few suppliers who can do it (see my summary in my reply to Simon, above).

Thanks for all your support, guys.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Wed, 30 Jan 2019 07:48:33 GMT

I asked for quotations from a few PCB manufacturers. Here is my summary...

- Elprint confirmed, that they had experience with nRF52840, and they can do the small via-in-pads within 5 days.

- Eurocircuits proposed some modifications to the inner pad rows (bigger and oval form). 5-7 days manufacturing time, too.

- PCBway (aka PCBcart) from china stated that they can to the small via-in-pads, too.

- Würth: Although they are said to be a high quality manufacturer, they stated that they cannot do these small via-in-pads. (Perhaps they don't do it, BECAUSE they are high quality. Other manufacturers might accept smaller pad dimensions and thus lower quality...??)

Because we used Eurocircuits in the past, we chose this one for our purposes.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

AmbystomaLabs — Wed, 23 Jan 2019 14:42:55 GMT

Again, you just need to google HDI, laser drilled, microvia, etc. There are at least a hundred manufacturers out there.

This is Sierra Circuits capabilities. I have never used them so can't give a personal reference.

https://www.protoexpress.com/content/capability.jsp

Here's some company called ESI touting their pretty CO2 lasers.

https://www.esi.com/solutions/pcb-processing/high-density-interconnect/

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

AmbystomaLabs — Wed, 23 Jan 2019 14:35:22 GMT

There are many, many pcb manufacturers capable of doing via in pad. I think your issue is that you are searching the wrong way. Almost none of the via in pad is done with traditional drilling techniques. A 3 mil drill is just too small and breaks easily.

You need to look for manufacturers with laser drilling equipment. Via in pad is normally done with laser drilled via and then you complement the board with traditional drilled vias. Via in pad is a 20 year old technique and is manufactured worldwide.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Beat — Wed, 23 Jan 2019 13:30:42 GMT

Hi Simon,

Thanks for your hints.

Unfortunately, the minimum PCB capabilities stated on the websites of both, Elprint and Eurocircuits, do not meet the nRF52840's requirements. Nevertheless, I try to get in contact with them and clarify. I will report the results here, as soon as I've got their replies.

RE: PCB prototype supplier meeting nRF52840 via-in-pad requirements

Simonr — Wed, 23 Jan 2019 13:08:07 GMT

I recommend you try Elprint. They usually have quick manufacturing times, however I have yet to try with an nRF52840 package. I also found Eurocircuits which seems to support the nRF52840 package. Other suggestions from the community are of course welcome as well.

Best regards,

Simon