CC1352R: Reference layout for this MCU

Jorge De La Rocha

Part Number: CC1352R

Looking for a reference layout for the CC1352R. Particularly, the 48MHz and 32.678KHz recommended layouts. Can these crystals be placed on opposite layer from MCU. (4-layer board)

over 4 years ago

0 YiKai Chen over 4 years ago

Guru 735695 points

Try to refer to LPSTK-CC1352R Design Files

0 Jorge De La Rocha over 4 years ago

Prodigy 150 points

Hi YiKai, Is it a bad practice to place the crystals on opposite side of MCU?

0 YiKai Chen over 4 years ago in reply to Jorge De La Rocha

Guru 735695 points

I don't have experience to place the crystals on opposite side of MCU but I don't think it's a good practice.

+1 TER over 4 years ago in reply to YiKai Chen

TI__Guru**** 317180 points

The recommendation is to place the xtals on the same side as the chip.

For a very area constrained layout it's an option but it means higher risk.

- We don't have any experience of placing the xtals on the other side and we have therefore not any guide on how this should be done.

- As I see it, it's two potential issues:

- The inductance in the vias, if these impact the xtal in some way

- Exposure to noise. Any noise picked up of the two lines going to the xtal will go directly into RF (for the 48 MHz xtal). I find it more difficult to keep track of how the routing is done and noise sources when the xtals are nor placed on the same layer as the chip.

0 Jorge De La Rocha over 4 years ago in reply to TER

Prodigy 150 points

YiKai, TER, This would be my hunch as well. We do have an area-constraint layout but we will try to fit them both on same side if possible.

Thank you.

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CC1352R: Reference layout for this MCU