nRF5340-CMAA replacement?

[Greg0]

For just a first test board off of Thingy 91x design, can nRF5340-CMAA be replaced with nRF5340-CLAA? What's the downside of doing that? Documentation says it's not recommended for new designs, but can't find details.

[Samruddhi Jadhav]

Hi,

The nRF5340-CLAA isn't recommended for new designs. The CMAA is a newer addition. In contrast to CMAA, the CLAA has smaller solder balls so there may be a chance that it doesn't properly fit on same landing pads. Also, CMAA and CLAA have different mechanical dimensions and internal bonding. This means that the footprint for the PCB will need an update and so would the RF matching network. 

Best Regards,

Samruddhi

[Samuel Carey]

Can you please confirm if the CLAA will or will not fit on CMAA pads? Also, please confirm that the RF will require different matching characteristics. The CMAA is currently unavailable and I need to know if I can use CLAA as a replacement.