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jawac_2707861
Level 1
Level 1

Here's my schematic. (Big photo see appendix)I try to use AP6234 module (CYW43340 solution) with STM32 in my project.

sch.PNG

But when I finish my layout and after manufacture, I met a strange problem:

When I use WICED SDK with snip.scan demo, the AP6234 only scans 2.4G APs.

And I tried to heat the board, and let the module maintain 100℃, now the scan result contains 5G APs.

But When the module cools down, it still only scans 2.4G APs.

I also tried the board called redbear duo:

https://github.com/redbear/Duo/blob/master/hardware/schematic/duo-schematic-v1.0.pdf

I moved the module to this board, the AP6234 works fine.

The strangest thing is my schematic is same as redbear-DUO board.

It's very strange, I don't know how to do. Who can help me?Thanks.

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1 Solution
jawac_2707861
Level 1
Level 1

I finally solved this problem.

This problem seems caused by the oscillator. The frequency of the 37.4MHz oscillator is not accurate enough. I changed one of the load capacitor of the oscillator ,and my circuit works fine now.

View solution in original post

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2 Replies
GauravS_31
Moderator
Moderator
Moderator
250 solutions authored 250 sign-ins First comment on KBA

Please attach the gerber files and bill of materials of your design for evaluation. In your schematic, you have shown 50 ohms for your Antenna. Did you use matching network components or did you perform impendance matching by modifying the trace layout?

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jawac_2707861
Level 1
Level 1

I finally solved this problem.

This problem seems caused by the oscillator. The frequency of the 37.4MHz oscillator is not accurate enough. I changed one of the load capacitor of the oscillator ,and my circuit works fine now.

0 Likes