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Help Validating PCB Design
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microcompiler:
I was reviewing the datasheet for the BNO055 and I fined this tidbit of info on page 100 "When an internal clock is used, both pins XIN32 and XOUT32 can be left open. The internal clock of the BNO055 can have clock deviation up to +3%".  I'm not sure how much this would throw off the actual measurements from the sensor. 
microcompiler:

--- Quote from: theatrus on May 02, 2017, 04:17:12 pm ---
--- Quote from: pigrew on May 02, 2017, 03:16:38 pm ---For the antenna track, it looks short enough that being exactly 50 ohms may not be so important. Find a coplanar waveguide calculator online, and adjust your track width/spacing to match its result. However, I would move the inductor so that its pad rests directly in the middle of the RF line, so you do not have a stub.

I also see a few acute angles on the board that you should get rid of.

--- End quote ---

Yeah, agree - the super short length is going to forgive any minor mistakes. For a CPW (grounded) calculation on 2 layer FR-4, a width of about 35mil with a spacing of 8mil gets you to ~53 ohms, which is plenty close enough (as the FR-4 isn't consistent, etc etc). The current design looks more like 10/10 spacing/width which is 82ohms - not great.

Second the stub elimination advice.

--- End quote ---

I think I have everything finalized and now know more about CPW calculation the when I started this project after some google searching I was able to calculate a trace with 56ohms.  Using dielectric constant: 3.95 / width: .8mm /gap:  .152mm thickness: 1.5mm.  Thanks for your feedback.
microcompiler:
I would like to start by thanking everyone for the advice and feedback on this project.  This last week has been almost entirely consumed (other then work) by reviewing every datasheet from start to finish and YouTube videos on PCB design principals. Here are the items I have hopefully addressed from everyone's comments.

1. Cleaned up the active antenna traces and calculated CPW of the trace to be 56ohms and added components for an active antenna .
2. Cleaned up the grounding and added vias at several points on the board.
3. Switched CAP and RES to 0805 package size (I'm going to try to hot plate my first prototype board).
4. Finalized my BOM and would love any feedback you might have on component selection. 

Here is what hopefully should be my final version. Any feedback would be great. 





pigrew:

--- Quote from: microcompiler on May 08, 2017, 02:25:08 am ---I would like to start by thanking everyone for the advice and feedback on this project.  This last week has been almost entirely consumed (other then work) by reviewing every datasheet from start to finish and YouTube videos on PCB design principals. Here are the items I have hopefully addressed from everyone's comments.

--- End quote ---
IC3 looks like it has no solder mask between the pins. I'd reduce its solder mask expansion until you have maybe about 6.5 mil (depends on the pcb fabricator) of mask between the pins. My fabricator usually suggests an expansion value of 1mil for 0.5mm pitch parts.
stevelup:
Watch your current limiting resistors on the RGB LED - it's unlikely that you want them all to be the same. The red diode has a forward voltage of 2V, the green and blue 3.2V
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