CC3235S: PCB copper issue

Cherry Zhou

Mastermind 22235 points

Part Number: CC3235S

Hi team,

The PCB of the CC3235 Launchpad dose not have copper laying on the part of the blue box in the following figure, why?

Thanks.

Best Regards,

Cherry

over 2 years ago

0 Dylan Hubbard over 2 years ago

TI__Mastermind 46295 points

Hi Cherry,

I don't think I'm following what you are asking. Are you referring to the top layer?

0 Cherry Zhou over 2 years ago in reply to Dylan Hubbard

TI__Mastermind 22235 points

Hi Dylan,

Thanks for your support.

Dylan Hubbard said:
Are you referring to the top layer?

Yes, why isn't the top layer have copper?

Thanks and Regards,

Cherry

0 Dylan Hubbard over 2 years ago in reply to Cherry Zhou

TI__Mastermind 46295 points

Hey Cherry,

All of the red you see is copper - there is copper in the circled area.

0 Cherry Zhou over 2 years ago in reply to Dylan Hubbard

TI__Mastermind 22235 points

Hi Dylan,

But the circled part in PCB is a non-copper area as the following figure:

Thanks and Regards,

Cherry

0 Dylan Hubbard over 2 years ago in reply to Cherry Zhou

TI__Mastermind 46295 points

Hey Cherry,

Just to be clear, that doesn't exactly mean there is no copper in that area. I can't say exactly why it was done this way since I'm not the specific designer, but I expect it has to do with the fact that there isn't much room for the top layer GND pour to flow into that area. It was likely creating fingers or just not pouring at all into that area so this was just a way to clean it up. Another plausible reason could be that they didn't want to connect those decoupling caps GNDs to the top layer for noise purposes. Some of those supplies power the RF circuitry and its good to isolate them from any digital return currents - there are quite a bit of digital signals connected to the header on the right.

Wi-Fi

Wi-Fi forum

CC3235S: PCB copper issue