PCB - PCA10040's Stack-up question

RE: PCB - PCA10040's Stack-up question

bjorn-spockeli — Fri, 13 Jan 2017 15:03:23 GMT

What I mean is that if L1( top copper layer) and L2( bottom copper layer) are 0.018 mm thick, then the thickness of the FR-4 substrate ( dielectric layer) between L1 and L2 must be set to 1.6 mm - 2*0.018mm = 1.56400mm. The L chosen in AppCad is just a random value, i.e. you will have to adjust this so that it matches your layout.

RE: PCB - PCA10040's Stack-up question

MANGO — Fri, 13 Jan 2017 05:44:39 GMT

Hi, Bjørn. Yes, your assumption, set the thickness to 1.6mm, is correct.

Can you explain more about the

If this is just the substrate, i.e. the material inbetween
the copper layers on the top and bottom,
then you will have to subtract the thickness
of those layers form (from typo) 1.6mm.

I couldn't understand what you've meant.

Lastly, about the picture of AppCAD that shows the parameters of the coplanar transmission,

is the parameter L (length) is really 1000 mils (25.4 mm)?

That looks quite long compared to the real PCA10040.

-Best Regards

RE: PCB - PCA10040's Stack-up question

bjorn-spockeli — Thu, 12 Jan 2017 10:31:40 GMT

I also do not know what IT158 refers to, I am assuming that its some kind of substrate. We do not produce the DKs ourselves, so this is sorted by the third-party manufacturer we use. If you're making a 2 layer 1.6mm thick FR-4 PCB then I would assume that you set the thickness to 1.6mm. If this is just the substrate, i.e. the material inbetween the copper layers on the top and bottom, then you will have to subtract the thickness of those layers form 1.6mm.

RE: PCB - PCA10040's Stack-up question

MANGO — Thu, 12 Jan 2017 03:41:02 GMT

I see. Then, in the family section, what's the "IT158"?

The PCB manufacturer that I'm working with doesn't recognize the "IT158".

More importantly, due to cost, I'm going to make 2 layered, 1.6mm thick, FR-4 PCB. Then the thickness of L3 and L4 will be eliminated. Then how much thickness should I set when creating a 2 layered PCB?

RE: PCB - PCA10040's Stack-up question

bjorn-spockeli — Tue, 10 Jan 2017 12:58:17 GMT

I do not know how to read chinese either, but the thickness is written in mm. If you need the thickness of the substrate then the its 0.0180mm*2 - 1.6mm.

RE: PCB - PCA10040's Stack-up question

MANGO — Tue, 10 Jan 2017 12:24:10 GMT

Wow. Thanks for the detailed picture. Unfortunately, I don't know how to read Chinese.

What do the Chinese letters mean in English?

RE: PCB - PCA10040's Stack-up question

bjorn-spockeli — Tue, 10 Jan 2017 12:10:46 GMT

I only know the stackup of the nRF51 DK, but I think the stack up will be fairly similar since the design of the nRF5x DKs are close to identical.

The coplanar transmission line on a 2-layer 1.6mm thick, FR-4 PCB should be designed as shown below